summaryrefslogtreecommitdiff
path: root/graphics/circuit_macros/libcct.m4
blob: f8a98a84c082fec75d852c0959e9d06c0b454b83 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
divert(-1)
  libcct.m4

* Circuit_macros Version 9.1, copyright (c) 2019 J. D. Aplevich under     *
* the LaTeX Project Public License. The files of this distribution may    *
* be redistributed or modified provided that this copyright notice is     *
* included and provided that modifications are clearly marked to          *
* distinguish them from this distribution.  There is no warranty          *
* whatsoever for these files.                                             *

define(`libcct_')
ifdef(`libgen_',,`include(libgen.m4)divert(-1)')

`==============================================================================
HINTS:

THE ARGUMENTS of circuit elements are optional; if omitted, default values
   are assumed.

TWO-TERMINAL ELEMENTS are constructed as follows, with variations:

   # Draw the initial invisible line (default length rp_len), and set the
   #   direction cosines:
   eleminit_(`$1')

   # Element body height and width
   define(`m4v',...)define(`m4h',...)

   # Visible lines:
   { line to rvec_(rp_len/2-m4h/2,0)
     (element body lines)
     line to rvec_(rp_len/2-m4h/2,0) }

   # The invisible body block:
   {[box invis ht_ m4v wid_ m4h ] at rvec_(rp_len/2,0)}

   # The final invisible line:
   line to rvec_(rp_len,0) invis

A side effect of the eleminit_ macro is to change the current drawing angle.

NON-TWO-TERMINAL ELEMENTS are usually constructed within a block:

   set dimension parameters
   [ set size and direction from the initial linespec argument
     set orientation
     draw internal elements
     define internal locations
     ]

   If there is a linespec argument, it determines orientation
   but not the placement of the element, since [] blocks are placed
   as if they were boxes.

==============================================================================
CUSTOMIZATIONS:

   The non-two-terminal circuit elements enclosed in [] blocks allow
   a final argument not shown in the argument list.  The last argument is
   expanded just before exit from the [] block to allow custom additions
   to the elements.

   Subcomponents of a circuit element are drawn selectively according
   to a "dna_" string and a sequence of calls to sc_draw(`dna_',arg2,arg3,arg4).
   If the second argument of sc_draw is a substring of the first, it is deleted
   from the first and the third argument is expanded, otherwise the fourth
   argument (which may be null) is expanded.

==============================================================================

DEBUGGING: The statement
     print "`$0'($@)" ;
   inserted into a macro will display the macro name and current arguments

==============================================================================
 This file redefines default arrow dimensions and the dotrad_ macro.
=============================================================================='

                                `capacitor( linespec,[char][+],R,height,wid )
                                 char:
                                  F or none: flat plates
                                  C = polarized, curved plate
                                  E = polarized rectangular plates
                                  K = filled rectangular plates
                                  M = rectangular plates
                                  N = one rectangular plate
                                  P = alternate polarized
                                  + = polarity sign to right of drawing dir
                                  +L =polarity sign to left
                                 arg3 = R: reversed orientation
                                 arg4 = height (defaults F: dimen_/3
                                   C,P: dimen_/4, E,K: dimen_/5)
                                 arg5 = wid (defaults F: height*0.3,
                                   C,P: height*0.4, E,K: height) '
define(`capacitor',
 `ifelse(`$3',R,`reversed(`capacitor',`$1',`$2',,shift(shift(shift($@))))',
 `eleminit_(`$1')
  define(`m4ctype',ifelse(`$2',,F,`$2',+,F,`$2',+L,F,`$2'))dnl
  m4_dna(`m4ctype',+L)`'m4_dna(`m4ctype',+)dnl
  { ifelse(m4ctype,F,
   `define(`m4cht',`ifelse(`$4',,`dimen_/3',`($4)')')dnl
    define(`m4cwd',`ifelse(`$5',,`m4cht*0.3',`($5)')')dnl
      line to rvec_(rp_len/2-m4cwd/2,0)
      {line from rvec_(0,-m4cht/2) \
          to rvec_(0,m4cht/2)}
      move to rvec_(m4cwd,0)
      {line from rvec_(0,-m4cht/2) \
          to rvec_(0,m4cht/2)}
      line to rvec_(rp_len/2-m4cwd/2,0) ',
  m4ctype,C,
   `define(`m4cht',`ifelse(`$4',,`dimen_/4',`($4)')')dnl
    define(`m4cwd',`ifelse(`$5',,`m4cht*0.4',`($5)')')dnl
    define(`m4cr',`dimen_*0.25')dnl
     line to rvec_(rp_len/2-m4cwd/2,0)
     {line from rvec_(0,-m4cht/2) \
          to rvec_(0,m4cht/2)}
     {arc cw from rvec_(m4cwd,-m4cht/2) \
          to rvec_(m4cwd,m4cht/2) \
        with .c at rvec_(m4cwd+sqrt((m4cr)^2-(m4cht/2)^2),0) }
     line from last arc.c+vec_(-m4cr,0) \
          to rvec_(rp_len/2+m4cwd/2,0) ',
  m4ctype,P,
   `define(`m4cht',`ifelse(`$4',,`dimen_/4',`($4)')')dnl
    define(`m4cwd',`ifelse(`$5',,`m4cht*0.4',`($5)')')dnl
    define(`m4cr',`dimen_*0.25')dnl
     line to rvec_(rp_len/2-m4cwd/2,0)
     {line from rvec_(m4cwd,-m4cht/2) \
          to rvec_(0,-m4cht/2) \
        then to rvec_(0,m4cht/2) \
        then to rvec_(m4cwd,m4cht/2) }
     {line from rvec_(m4cwd*2/3,-m4cht*3/8) \
          to rvec_(m4cwd*2/3,m4cht*3/8)}
     line from rvec_(m4cwd*2/3,0) \
          to rvec_(rp_len/2+m4cwd/2,0) ',
  m4ctype,E,
   `define(`m4cht',`ifelse(`$4',,`dimen_/5',`($4)')')dnl
    define(`m4cwd',`ifelse(`$5',,`m4cht',`($5)')')dnl
    define(`m4cs',`(m4cwd/3.2)')dnl
     line to rvec_(rp_len/2-m4cwd/2,0)
     m4linethicktemp = linethick; thinlines_
     { lbox(m4cs,m4cht) }
     move to rvec_(m4cwd,0)
     {ifsvg(`lbox(-m4cs,m4cht,fill_(0))',`m4fshade(m4fill,lbox(-m4cs,m4cht))')}
     linethick_(m4linethicktemp)
     line to rvec_(rp_len/2-m4cwd/2,0) ',
  m4ctype,M,
   `define(`m4cht',`ifelse(`$4',,`dimen_/5',`($4)')')dnl
    define(`m4cwd',`ifelse(`$5',,`m4cht',`($5)')')dnl
    define(`m4cs',`(m4cwd/3.2)')dnl
     line to rvec_(rp_len/2-m4cwd/2,0)
     m4linethicktemp = linethick; thinlines_
     { lbox(m4cs,m4cht) }
     move to rvec_(m4cwd,0)
     { lbox(-m4cs,m4cht) }
     linethick_(m4linethicktemp)
     line to rvec_(rp_len/2-m4cwd/2,0) ',
  m4ctype,K,
   `define(`m4cht',`ifelse(`$4',,`dimen_/5',`($4)')')dnl
    define(`m4cwd',`ifelse(`$5',,`m4cht',`($5)')')dnl
    define(`m4cs',`(m4cwd/3.2)')dnl
      line to rvec_(rp_len/2-m4cwd/2,0)
      {ifsvg(`lbox(m4cs,m4cht,fill_(0))',`m4fshade(m4fill,lbox(m4cs,m4cht))')}
      move to rvec_(m4cwd,0)
      {ifsvg(`lbox(-m4cs,m4cht,fill_(0))',`m4fshade(m4fill,lbox(-m4cs,m4cht))')}
      line to rvec_(rp_len/2-m4cwd/2,0) ',
  m4ctype,N,
   `define(`m4cht',`ifelse(`$4',,`dimen_/5',`($4)')')dnl
    define(`m4cwd',`ifelse(`$5',,`m4cht*2/3',`($5)')')dnl
    define(`m4cs',`(m4cwd/3.2*3/2)')dnl
      line to rvec_(rp_len/2-m4cwd/2,0)
      { lbox(m4cs,m4cht) }
      move to rvec_(m4cwd,0)
      {line from rvec_(0,m4cht/2) to rvec_(0,-m4cht/2) }
      line to rvec_(rp_len/2-m4cwd/2,0) ')
  }
  ifinstr(`$2',+L,
   `{ move to rvec_(rp_len/2-m4cwd/2-m4cht/3,m4cht/3)
      {line thick 0.5 from rvec_(m4cht/6,0) \
          to rvec_(-m4cht/6,0)}
      line thick 0.5 from rvec_(0,m4cht/6) \
          to rvec_(0,-m4cht/6)}',
   `$2',+,
   `{ move to rvec_(rp_len/2-m4cwd/2-m4cht/3,-m4cht/3)
      {line thick 0.5 from rvec_(m4cht/6,0) \
          to rvec_(-m4cht/6,0)}
      line thick 0.5 from rvec_(0,m4cht/6) \
          to rvec_(0,-m4cht/6)}')
  {[box invis ht_ m4cht wid_ m4cwd ] at rvec_(rp_len/2,0)}
  line to rvec_(rp_len,0) invis ')')

                                `resistor( linespec, cycles, chars, cycle wid)
                                 chars : E=ebox
                                         ES=ebox with slash
                                         Q=offset
                                         H=squared (default 3 cycles)
                                         N=IEEE (default 3 cycles)
                                         V=varistor variant
                                         R=to right of drawing direction
                                 arg4: cycle width, default dimen_/6'
define(`resistor',
`define(`m4h',`ifelse(`$4',,`dimen_/6',`($4)')/4')dnl
 ifinstr(
 `$2',E,
   `ebox(`$1',shift(shift($@)))',
 `$3',ES,
   `ebox(`$1',shift(shift(shift($@))))
    {line from last line.c+vec_(m4wd*0.3,m4ht/2) \
            to last line.c+vec_(-m4wd*0.3,-m4ht/2)}
    line invis from 2nd last line.start to 2nd last line.end',
 `$3',E,
   `ebox(`$1',shift(shift(shift($@))))',
 `$3',V,
   `M4_varistor($@)',
 `define(`dna_',ifelse(`$3',,N,`$3',R,N,`$3'))dnl
  eleminit_(`$1')
  sc_draw(`dna_',N,
   `define(`m4n',`ifelse(`$2',,6,`eval(2*($2))')')dnl  Default resistor:
    define(`m4v',2)dnl
    if m4h*m4n*2 > rp_len then { eleminit_(to rvec_(m4h*m4n*2,0)) }
    tr_xy_init(last line.c, m4h, sc_draw(`dna_',R,-))dnl
    { line from last line.start to tr_xy(-m4n,0)\
      for_(2,m4n,2,
        `then to tr_xy(eval(2*m4x-3-m4n), m4v) \
         then to tr_xy(eval(2*m4x-1-m4n),-m4v) \')dnl
         then to tr_xy(m4n, 0) \
         then to last line.end
      [box invis ht_ m4h*m4v*2 wid_ m4h*m4n*2] at 2nd last line.c
      }')
  sc_draw(`dna_',Q,
   `define(`m4n',`ifelse(`$2',,6,`eval(2*($2))')')dnl
    define(`m4v',2)dnl
    if m4h*m4n*2 > rp_len then { eleminit_(to rvec_(m4h*m4n*2,0)) }
    tr_xy_init(last line.c, m4h, sc_draw(`dna_',R,-))dnl
    { line from last line.start to tr_xy(-m4n,0)\
      for_(2,m4n,2,
       `then to tr_xy(eval(2*m4x-2-m4n), m4v*2) \
        then to tr_xy(eval(2*m4x-m4n),0) \')dnl
        then to tr_xy(m4n, 0) \
        then to last line.end
      [box invis ht_ m4h*m4v*2 wid_ m4h*m4n*2] at 2nd last line.c + ta_xy(0,m4v)
      }')
  sc_draw(`dna_',H,
   `define(`m4n',`ifelse(`$2',,5,`eval(2*($2)-1)')')dnl
    define(`m4hh',`m4h*6/5')dnl
    define(`m4v',7/3)dnl
    if m4hh*m4n*2 > rp_len then { eleminit_(to rvec_(m4hh*m4n*2,0)) }
    tr_xy_init(last line.c, m4hh, sc_draw(`dna_',R,-))dnl
    { line from last line.start to tr_xy(-m4n,0)\
      for_(-m4n,m4n,2,
       `ifelse(eval(((m4x+m4n)/2)%2),0,
         `then to tr_xy(m4x,m4v) \
          then to tr_xy(eval(m4x+2),m4v) \',
         `then to tr_xy(m4x,0) \
          ifelse(m4x,m4n,,`then to tr_xy(eval(m4x+2),0)')\')')dnl
      then to tr_xy(m4n, 0) \
      then to last line.end
      [box invis ht_ m4hh*m4v wid_ m4hh*m4n*2] at 2nd last line.c+(0,m4hh*m4v/2)
      }')
  line invis from 2nd last line.start to 2nd last line.end ')')

define(`M4_varistor',`eleminit_(`$1')
   define(`m4wd',`dimen_/2')dnl
   define(`m4ht',`dimen_/4')dnl
   {line to rvec_(max(0,rp_len/2-m4wd/2),0)
   {m4fshade(m4fill,line to rvec_(0,ifinstr(`$3',R,,-)m4ht/2) \
        then to rvec_(m4wd/2,0) \
        then to Here)}
    move to rvec_(m4wd,0)
    m4fshade(m4fill,line to rvec_(0,ifinstr(`$3',R,-)m4ht/2) \
        then to rvec_(-m4wd/2,0) \
        then to Here)
    line to rvec_(max(0,rp_len/2-m4wd/2),0) }
  {[box invis ht_ m4ht wid_ m4wd] at rvec_(rp_len/2,0)}
   line to rvec_(rp_len,0) invis ')

                         `potentiometer(linespec, cycles,
                            fractional pos, length, fractional pos, length,...)
                          Resistor in a block, tapped at fractional positions
                          with specified (possibly negative) arrow lengths.
                          Taps are labelled T1, T2, ...
                          Uses side effects of resistor macro'
define(`potentiometer',`[R: resistor(`$1',`$2')
  Start: R.start; End: R.end; C: 0.5 between Start and End
  m4pot_arrows(1,ifelse(`$3',,0.5,`$3'),ifelse(`$4',,`dimen_*5/12',`$4'),
  shift(shift(shift(shift($@)))))] ')
define(`m4pot_arrows',`ifelse(`$2',,,`
  x = (`$2')*2*m4n+1; x = (int(x)%4)+(x-int(x))
  M4_Tmp: `$2' between last [].c-vec_(prod_(m4n,m4h),0) \
    and last [].c+vec_(prod_(m4n,m4h),0)
  T`$1': M4_Tmp + vec_(0,ifelse(`$3',,`dimen_*5/12',`$3'))
  { arrow from T`$1' to M4_Tmp+vec_(0,m4h*m4v*(1-(x-2)*sign(x-2))) }
  m4pot_arrows(incr($1),shift(shift(shift($@))))')')

                         `KelvinR(cycles,[R],cycle wid)
                          IEEE resistor with kelvin taps added
                          if arg1 is blank then a [] block is used'
define(`KelvinR',`[
  M4R: resistor(,`$1',,`$3') define(`m4kRm',`ifinstr(`$2',R,-,+)')
  { dot(at tr_xy(-m4n,0),lthick)
    line to tr_xy(-m4n-1,m4kRm`'2) then to tr_xy(-m4n-1,m4kRm`'4)
    T1: Here
    dot(at tr_xy(m4n,0),lthick)
    line to tr_xy(m4n+1,m4kRm`'2) then to tr_xy(m4n+1,m4kRm`'4)
    T2: Here }
  Start: M4R.start; End: M4R.end; C: M4R.c
  `$4' ]') ')

                         `FTcap(chars)
                          Feed-through capacitor; composite element
                          derived from a two-terminal element.
                          Defined points: .Start, .End, .C
                          chars: A|B|C|D element type'
define(`FTcap',`[ define(`FTctyp',`ifelse(`$1',,A,`$1')')dnl
  ifelse(FTctyp,A,
   `capacitor(to vec_(dimen_*2/3,0))
    Start: last line.start; End: last line.end; C: last line.c
    Conductor: line from C+vec_(0,dimen_/3) to C+vec_(0,-dimen_/3)
    T1: last line.start; T2: last line.end',
  FTctyp,B,
   `capacitor(to vec_(dimen_*2/3,0),C)
    Start: last line.start; End: last line.end; C: last line.c
    r = last arc.rad-hlth
    T1: (0.5 between 2nd line.end and last arc.c-vec_(r,0)) + vec_(0,dimen_/3)
    T2: T1+(0,-dimen_*2/3)
    Conductor: line from T1 to T2',
  FTctyp,C,
   `line to vec_(dimen_*2/3,0)
    Start: last line.start; End: last line.end; C: last line.c
    rp_a = rp_ang
    capacitor(from C to C-vec_(0,dimen_/10),C)
    point_(rp_a)
    line from last line.end to last line.end-vec_(0,dimen_/3)
    T: Here',
  FTctyp,D,
   `Start: Here
    capacitor(to rvec_(dimen_/3,0),C)
    C: Here
    { line to rvec_(0,-dimen_/3); T: Here }
    End: rvec_(dimen_/3,0)
    rp_a = rp_ang
    capacitor(from End to Here,C)
    point_(rp_a)')
  `$2' ]')

                         `addtaps([ahead | type=ahead;name=Name],
                            fractional pos, length, fractional pos, length,...)
                          Tap names are Tap1, Tap2, ...  or
                          Name1, Name2, ... if specified
                          ahead = blank or one of . - <- -> <-> '
define(`addtaps',`
ifelse(`$2',,`undefine(`m4tap_x')popdef(`m4type')popdef(`m4name')',
 `ifdef(`m4tap_x',`define(`m4tap_x',incr(m4tap_x))',
  `define(`m4tap_x',1) M4tap_w: last [].w_; M4tap_e: last [].e_
   setkey_(`$1',type,`$1',N)setkey_(`$1',name,Tap,N)dnl
   M4tap_xy: (last [].wid_,last [].ht_)')
  {define(`m4tapl',`ifelse(`$3',,`dimen_/3',`$3')')dnl
  move to (`$2' between M4tap_w and M4tap_e) + vec_(0,sign(m4tapl)*M4tap_xy.y/2)
  ifinstr(m4type,.,`{dot(,lthick)}define(`m4type')');dnl
  line ifelse(m4type,-,,m4type) to rvec_(0,m4tapl)
  m4name`'m4tap_x: Here }
  addtaps(,shift(shift(shift($@))))')')

                         `tapped(`two-terminal element',[. | <- | -> | <->],
                            fractional pos, length, fractional pos, length,...)
                          Draw the two-terminal element and taps in a [] block'
define(`tapped',`[ $1
  Start: last line.start; End: last line.end; C: last line.c
  addtaps(shift($@)) ]')

                         `b_current( label, above_|below_, O[ut],
                            S[tart]|E[nd], frac )
                          Branch current for last-drawn element.  The arrowhead
                          is drawn frac (default 2/3) of the way between
                          the line end and element body.'
define(`b_current',
 `define(`m4y',`ifelse(`$5',,2/3,`($5)')')dnl
  define(`m4v',`ifinstr(`$4',E,
   `ifinstr(`$3',O,-)',`ifinstr(`$3',O,,-)')arrowht')dnl
  define(`m4h',`(rp_len-last [].wid_)/2')
  { move to last line.start+vec_(ifinstr(`$4',E,`rp_len-')dnl
    ifinstr(`$3',O,`(m4h-arrowht)*m4y',`(m4h*m4y+arrowht/3)'),0)
    arrow <- m4c_l to rvec_(m4v,0) ifelse(`$1',,,
   `m4lstring(`$1',"sp_`iflatex(`$ `$1'$',`$1')'sp_") \
     ifelse(`$2',,`above_',`$2')')}')

                                `larrow( label, <-, separation )
                                 Arrow alongside the left of the last-drawn
                                 element'
define(`larrow',`define(`m4h',`min(lin_leng(last line),linewid)/2')dnl
 define(`m4v',`ifelse(`$3',,`5pt__',`($3)')')dnl
 {arrow `$2' from last [].n_+vec_(-m4h,m4v) \
    to last [].n_+vec_(m4h,m4v) \
  m4lstring(`$1',"sp_`iflatex(`$ `$1'$',` $1')'sp_") above_}')

                                `rarrow( label, <-, separation )
                                 Arrow alongside the right of the last-drawn
                                 element'
define(`rarrow',`define(`m4h',`min(lin_leng(last line),linewid)/2')dnl
 define(`m4v',`ifelse(`$3',,`5pt__',`($3)')')dnl
 {arrow `$2' from last [].s_+vec_(-m4h,-m4v) \
    to last [].s_+vec_(m4h,-m4v) \
  m4lstring(`$1',"sp_`iflatex(`$ `$1'$',` $1')'sp_") below_}')

                                `inductor( linespec,W|L,cycles,M|P,loop wid )
                                 W=wide arcs (default narrow); L=looped arcs
                                 M=metal core; P=powder core
                                 loop wid defaults W,L: dimen_/5,
                                                 other: dimen_/8'
define(`inductor',`eleminit_(`$1')
 define(`m4hlw',`ifelse(`$5',,`dimen_/10',`($5)/2')')dnl half loop wid
 define(`m4n',`ifelse(`$3',,4,`$3')')dnl
 ifelse(`$2',W,
  `m4Inductor',
 `$2',L,
  `m4Lnductor',
  `m4inductor(,ifelse(`$5',,,`($5)/2'))')
 ifelse(ifelse(`$4',M,T,`$4',P,T),T,`m4m_core(rvec_(rp_len/2,0),
     m4wd,m4ht+dimen_/24,dimen_/16,ifelse(`$4',P,dashed m4wd/(2*m4n+1)))
   define(`m4hs',`(dimen_/24+dimen_/16)')',`define(`m4hs',0)')
 {[box invis ht_ m4ht+m4hs+m4dp wid_ m4wd] \
   at rvec_(rp_len/2,(m4ht+m4hs-m4dp)/2)}
 line to rvec_(rp_len,0) invis ')
                                `Wide loop inductor'
define(`m4Inductor',`define(`m4ht',`(1+m4st)*m4hlw')dnl
 define(`m4dp',`(m4s2t-m4st)*m4hlw')define(`m4wd',((2*m4n-2)*m4c2t+2)*m4hlw)dnl
 { line to rvec_(rp_len/2-((m4n-1)*m4c2t+m4ct)*m4hlw,0); round
   arc cw from Here to rvec_(vscal_(m4hlw,m4ct+m4c2t,m4st-m4s2t)) \
      with .c at rvec_(vscal_(m4hlw,m4ct,m4st)); round
   for m4i=3 to m4n do { arc cw from Here to rvec_(vscal_(m4hlw,2*m4c2t,0)) \
      with .c at rvec_(vscal_(m4hlw,m4c2t,m4s2t)); round }
   arc cw from Here to rvec_(vscal_(m4hlw,m4ct+m4c2t,m4s2t-m4st)) \
      with .c at rvec_(vscal_(m4hlw,m4c2t,m4s2t)); round
   line to rvec_(rp_len/2-((m4n-1)*m4c2t+m4ct)*m4hlw,0) } ')
define(`m4ct',`Cos(25)')define(`m4st',`Sin(25)')
define(`m4c2t',`Cos(50)')define(`m4s2t',`Sin(50)')
                                `Looped inductor'
define(`m4Lnductor',`define(`m4ht',`m4hlw*10/8')dnl
 define(`m4dp',`m4hlw/2')define(`m4wd',(m4n+1)*m4hlw)dnl
 { line to rvec_(rp_len/2-m4wd/2,0); round
   spline ifdpic(0.55) \
          to rvec_(0,m4ht) for_(1,m4n,1,`\
      then to rvec_((m4x+0.3)*m4hlw, m4ht) \
      then to rvec_((m4x+0.3)*m4hlw,-m4dp) \
      then to rvec_((m4x-0.3)*m4hlw,-m4dp) \
      then to rvec_((m4x-0.3)*m4hlw, m4ht)\')\
      then to rvec_(m4wd,m4ht) \
      then to rvec_(m4wd,0)
   round; line to rvec_(rp_len/2-m4wd/2,0) }')
                                `Narrow inductor'
define(`m4inductor',`define(`m4ht',`ifelse(`$2',,`dimen_/16',`$2')')dnl
 define(`m4dp',0)define(`m4wd',m4n*m4ht*2)dnl
 ifelse(ifpstricks(T)`'ifmpost(T)`'ifpgf(T)`'ifsvg(T),T,
  `define(`m4y')',`undefine(`m4y')')dnl
 { line to rvec_((rp_len-m4wd)/2,0)
   ifdef(`m4y',`{line to rvec_(0,-hlth)};')
   for m4i=1 to m4n do {
     arc cw from Here to rvec_(m4ht*2,0) with .c at rvec_(m4ht,0)
     ifdef(`m4y',`{line to rvec_(0,-hlth)}') }
   line to rvec_((rp_len-m4wd)/2,0)} ')

                               `m4m_core(bottom ctr, length, ht offset,
                                 separation,linetype)
                                 Two lines for the metal core'
define(`m4m_core',`dnl
  {M4Core1: line from `$1'+vec_(-(`$2')/2,`$3') \
        to `$1'+vec_( (`$2')/2,`$3') `$5'
   M4Core2: line from M4Core1.start+vec_(0,`$4') \
        to M4Core1.end+vec_(0,`$4') `$5'}')

                                `transformer( linespec, L|R, np,
                                  [A|P][W|L][D1|D2|D12|D21], ns )
                                 2-winding transformer or choke:
                                 np = number of primary arcs
                                 ns = number of secondary arcs
                                 A = air core; P = powder (dashed) core
                                 W = wide windings; L = looped windings
                                 D1: phase dots at P1 and S1 ends; D2: dots
                                 at P2 and S2 ends; D12: dots at P1 and S2
                                 ends; D21: dots at P2 and S1 ends'
define(`transformer', `[ P1: Here define(`m4drt',m4dir)
 define(`m4WL',`ifinstr(`$4',W,W,`ifinstr(`$4',L,L)')')dnl
 define(`m4np',`ifelse(`$3',,4,(`$3'))')dnl
 define(`m4ns',`ifelse(`$5',,4,(`$5'))')dnl
 ifelse(`$1',,`mvw = max(\
  ifelse(m4WL,W,`dimen_/5*((m4np-1)*m4c2t+m4ct)',`m4np*dimen_/8'),dimen_*2/3)
  move to P1+vec_(mvw,0)',
  move `$1' )
 P2: Here
 TP: 0.5 between P1 and P2
 L1: inductor(from ifelse(`$2',R,`P2 to P1',`P1 to P2'),m4WL,`$3')
 define(`m4WP',m4wd)dnl
 define(`m4t',`ifelse(m4WL,W,((2*m4ns-2)*m4c2t+2)*m4hlw,m4WL,L,(m4ns+1)*m4hlw,
                      m4ns*m4ht*2)')dnl
 ifinstr(`$4',A,
  `move to last line.c+vec_(0,m4ht*ifelse(m4WL,W,3,m4WL,L,3,4))',
  `m4m_core(rvec_(-(rp_len/2),0),max(m4wd,m4t),m4ht+dimen_/12,dimen_/8,
     ifinstr(`$4',P,dashed m4wd/(2*m4n+1)))
   move to last line.c+vec_(0,m4ht+dimen_/12)')
 TS: Here
 S2: rvec_( ifelse(`$2',R,-)(ifelse(`$5',,rp_len/2,m4t/2)), 0 )
 S1: 2 between S2 and Here
 L2: inductor(from ifelse(`$2',R,`S1 to S2',`S2 to S1'),m4WL,`$5')
 rpoint_(from P1 to P2) define(`m4WS',m4wd)
 ifinstr(`$4',D1,
   `m4trdot(P1,P2,-,m4WP,ifelse(`$2',R,-),D1:)
    ifinstr(`$4',D12,`m4trdot(S1,S2, ,m4WS,ifelse(`$2',R,,-),D2:)',
                     `m4trdot(S1,S2,-,m4WS,ifelse(`$2',R,,-),D2:)')',
  `$4',D2,
   `m4trdot(P1,P2,,m4WP,ifelse(`$2',R,-),D1:)
    ifinstr(`$4',D21,`m4trdot(S1,S2,-,m4WS,ifelse(`$2',R,,-),D2:)',
                     `m4trdot(S1,S2, ,m4WS,ifelse(`$2',R,,-),D2:)')')
  m4xpand(m4drt`'_)
 `$6' ]')
define(`m4trdot',`{`$6'dot(at (0.5 between `$1' and `$2') \
      +vec_(`$3'(`$4'+m4hlw)/2,`$5'dimen_/16), dotrad_/2)}')

                                `delay( linespec, width )'
define(`delay',`eleminit_(`$1')
 define(`m4ht',`ifelse(`$2',,`delay_rad_*2',`($2)')')dnl
 define(`m4wd',`m4ht*5/6')dnl
 { line to rvec_(rp_len/2-m4wd/2,0)
   { line from rvec_(m4ht/3,-m4ht/2) \
          to rvec_(0,-m4ht/2)\
       then to rvec_(0,m4ht/2) \
       then to rvec_(m4ht/3,m4ht/2)
     arc cw from Here to rvec_(0,-m4ht) with .c at rvec_(0,-m4ht/2) }
   move to rvec_(m4wd,0)
   line to rvec_(rp_len/2-m4wd/2,0) }
 { [box invis ht_ m4ht wid_ m4wd ] at rvec_(rp_len/2,0)}
 line to rvec_(rp_len,0) invis ')

                                `crystal xtal( linespec )'
define(`xtal',`eleminit_(`$1')
 define(`m4ht',`dimen_/4')define(`m4wd',`m4ht*2/3')define(`m4cs',`m4ht/3')dnl
 { line to rvec_(rp_len/2-m4wd/2,0)
   {line from rvec_(0,-m4ht/3) \
          to rvec_(0,m4ht/3)}
   { move to rvec_(m4wd/2-m4cs/2,0)
     line to rvec_(0,m4ht/2) \
       then to rvec_(m4cs,m4ht/2) \
       then to rvec_(m4cs,-m4ht/2) \
       then to rvec_(0,-m4ht/2) \
       then to Here }
   move to rvec_(m4wd,0)
   {line from rvec_(0,-m4ht/3) \
          to rvec_(0,m4ht/3)}
   line to rvec_(rp_len/2-m4wd/2,0) }
 {[box invis ht_ m4ht wid_ m4wd ] at rvec_(rp_len/2,0)}
 line to rvec_(rp_len,0) invis ')

                  `source( linespec,
                     V|v|I|i|AC|B|F|G|H|Q|L|N|P|R|S[C[r]|E[r]]]|T|X|U|other,
                     diameter, R, fill)
                     V = voltage source; v=alternate voltage source;
                     I = current source; i = alternate current source;
                     AC = AC source, B = bulb, F = fluorescent, G = generator,
                     Q = charge, L = lamp, N = neon, P = pulse, R = ramp,
                     SC = quarter arc, SE = arc; r = right orientation,
                     S = sinusoid,
                     T = triangle, X = interior X, U = square-wave,
                     other = custom interior label or waveform,
                     R = reversed polarity
                     arg 5 modifies the circle with e.g., color or fill'
define(`source',`ifelse(`$4',R,
 `reversed(`source',`$1',`$2',`$3',,shift(shift(shift(shift($@)))))',
 `eleminit_(`$1')
 define(`m4h',ifelse(`$3',,`sourcerad_',`($3)/2'))dnl
 ifelse(
 `$2',G,`m4_sourceGQ($@)',
 `$2',Q,`m4_sourceGQ($@)',
 `{ line to rvec_(rp_len/2-m4h,0)
    move to rvec_(m4h,0)
  { Src_C: circle rad m4h `$5' at Here }
  ifelse(`$2',,,
  `$2',F,`{ line from rvec_(-m4h,0) \
          to rvec_(-m4h/2,0)}
          { line from rvec_(-m4h/2,-m4h/2) \
          to rvec_(-m4h/2,m4h/2)}
          { line from rvec_(m4h/2,-m4h/2) \
          to rvec_(m4h/2,m4h/2)}
          { line from rvec_(m4h,0) \
          to rvec_(m4h/2,0)}',
  `$2',I,`{arrow from rvec_(-m4h*3/4,0) \
          to rvec_(m4h*3/4,0)}',
  `$2',i,`{line from rvec_(0,-m4h) \
          to rvec_(0,m4h)}',
  `$2',B,`{line from rvec_(-m4h,0) \
          to rvec_(-m4h*2/3,0)
           round
           arc ccw to rvec_(m4h*12/12,0) with .c at rvec_(m4h*12/24,0)
           arc ccw to rvec_(-m4h*2/3,0) with .c at rvec_(-m4h*1/3,0)
           arc ccw to rvec_(m4h*12/12,0) with .c at rvec_(m4h*12/24,0)
           round
           line to rvec_(m4h/3,0)}',
  `$2',H,`{ line from Here+(-m4h/2,-m4h/3) \
          to Here+(0,-m4h/3) \
             then to Here+(0,m4h/3) \
             then to Here+(m4h/2,m4h/3) }',
  `$2',L,`{line from rvec_(-m4h,0) \
          to rvec_(-m4h/4,0)
           round
           spline to rvec_(m4h/12,m4h*2/3) \
             then to rvec_(m4h*5/12,m4h*2/3) \
             then to rvec_(m4h/2,0)
           round
           line to rvec_(m4h*3/4,0)}',
  `$2',N,`{ {line from rvec_(-m4h,0) \
          to rvec_(-m4h/2,0)}
            for_(70,250,180,
            `{ line from rvec_(Rect_(m4h/2,-m4x)) \
          to rvec_(Rect_(m4h/2,m4x))
               round }
             { arc cw from rvec_(Rect_(m4h/2,m4x)) \
          to rvec_(Rect_(m4h/2,-m4x)) \
                 with .c at Here
               round }')
             {line from rvec_(m4h/2,0) \
          to rvec_(m4h,0)}}',
  `$2',V,`{"ifsvg(-,`$_-$')" at rvec_(-m4h/2,0) ifsvg(+(0,textht/10))}
          {"ifsvg(svg_small(+),`$_+$')" \
              at rvec_( m4h/2,0) ifsvg(+(0,textht/10))}',
  `$2',v,`{line from rvec_(-m4h,0) \
          to rvec_(m4h,0)}',
  `$2',AC,`{
    arc rad m4h/3 cw from Here-(m4h*2/3,0) \
        to Here with .c at Here-(m4h/3,0)
    arc rad m4h/3 ccw from Here to Here+(m4h*2/3,0) with .c at Here+(m4h/3,0)}',
  `$2',P,`{ line from Here+(-m4h/2,-m4h/4) \
        to Here+(-m4h/4,-m4h/4) \
            then to Here+(-m4h/4,m4h/4) \
            then to Here+(m4h/4,m4h/4) \
            then to Here+(m4h/4,-m4h/4) \
            then to Here+(m4h/2,-m4h/4) }',
  `$2',U,`{ line from Here+(-m4h/2,0) \
        to Here+(-m4h/2,m4h/3) \
            then to Here+(0,m4h/3) \
            then to Here+(0,-m4h/3) \
            then to Here+(m4h/2,-m4h/3) \
            then to Here+(m4h/2,0) }',
  `$2',R,`{ line from Here+(-m4h*2/3,-m4h/3) \
        to Here+(m4h/3,m4h/2) \
            then to Here+(m4h/3,-m4h/3) }',
  `$2',SCr,`{ arc cw from rvec_(-m4h,0) \
     to rvec_(0,-m4h) \
     with .c at rvec_(-m4h,-m4h) }',
  `$2',SC,`{ arc from rvec_(-m4h,0) \
     to rvec_(0,m4h) \
     with .c at rvec_(-m4h,m4h) }',
  `$2',SEr,`{ arc cw from Cintersect(Here,m4h,rvec_(0,-2*m4h),1.8*m4h,R) \
     to Cintersect(Here,m4h,rvec_(0,-2*m4h),1.8*m4h) \
     with .c at rvec_(0,-2*m4h) }',
  `$2',SE,`{ arc from Cintersect(Here,m4h,rvec_(0,2*m4h),1.8*m4h) \
     to Cintersect(Here,m4h,rvec_(0,2*m4h),1.8*m4h,R) \
     with .c at rvec_(0,2*m4h) }',
  `$2',S,`{ ifgpic(
    `arc rad m4h/3 cw from Here-(m4h*2/3,0) \
        to Here with .c at Here-(m4h/3,0)
     arc rad m4h/3 ccw from Here to Here+(m4h*2/3,0) with .c at Here+(m4h/3,0)',
    `savem4dir(`m4srcstack') right_
     sinusoid(m4h/2,twopi_/(m4h),pi_/2,-m4h/2,m4h/2) with .Origin at Here
     restorem4dir(`m4srcstack') ') }',
  `$2',T,`{ line from Here+(-m4h*3/4,-m4h/4) \
        to Here+(-m4h/4,m4h/4) \
            then to Here+(m4h/4,-m4h/4) \
            then to Here+(m4h*3/4,m4h/4) }',
  `$2',X,`define(`m4v',`m4h/sqrt(2)')dnl
    {line from rvec_(-m4v,m4v) \
          to rvec_(m4v,-m4v)}
    {line from rvec_(-m4v,-m4v) \
          to rvec_(m4v,m4v)}',
  `{$2}' )
  line from rvec_(m4h,0) \
          to rvec_(rp_len/2,0)} ')
  { [box invis ht_ m4h*2 wid_ m4h*2] at rvec_(rp_len/2,0) }
  line to rvec_(rp_len,0) invis ')')
                    `Internal to source macro:'
define(`m4_sourceGQ',
`{ line to rvec_(rp_len/2-3/2*m4h,0)
  {[C1: circle rad m4h
    L: C1+vec_(m4h/2, m4h*sqrt(3)/2) 
    R: C1+vec_(m4h/2,-m4h*sqrt(3)/2)
    C2: ifelse(`$2',G,`circle rad m4h',`arc rad m4h from R to L') \
      with .c at C1 +vec_(m4h,0)] at rvec_(m4h*3/2,0)}
  line from rvec_(m4h*3,0) \
          to rvec_(rp_len/2+3/2*m4h,0) } ')

                    `ttmotor( linespec, string, diameter, brushwid, brushht )'
define(`ttmotor',`eleminit_(`$1')
  define(`m4r',ifelse(`$3',,`sourcerad_',`($3)/2'))dnl
  define(`m4w',ifelse(`$4',,`sourcerad_/4',`($4)'))dnl
  define(`m4h',ifelse(`$5',,`sourcerad_/2',`($5)'))dnl
  define(`m4cr',`(m4r-sqrt(max(m4r*m4r-m4h*m4h/4,0)))')dnl
  { line to rvec_(max(rp_len/2-m4r-m4w,0),0)
    { line from rvec_(m4w+m4cr,m4h/2) \
          to rvec_(0,m4h/2) \
        then to rvec_(0,-m4h/2) \
        then to rvec_(m4w+m4cr,-m4h/2) }
    { TTM_C: circle rad m4r \
       at rvec_(m4w+m4r,0) ifelse(`$2',,,`m4lstring($2,"$2")') }
    move to rvec_((m4w+m4r)*2,0)
    { line from rvec_(-m4w-m4cr,m4h/2) \
          to rvec_(0,m4h/2) \
        then to rvec_(0,-m4h/2) \
        then to rvec_(-m4w-m4cr,-m4h/2) }
    line to rvec_(max(rp_len/2-m4r-m4w,0), 0) }
  { [box invis ht_ m4r*2 wid_ (m4r+m4w)*2] at last circle.c }
  line to rvec_(rp_len,0) invis ')

                                `Controlled source
                                 consource( linespec ,V|I|v|i, R )
                                 arg 4 can be used to modify the body with e.g.
                                   color or fill'
define(`consource',`ifelse(`$3',R,
 `reversed(`consource',`$1',`$2',,shift(shift(shift($@))))',
 `eleminit_(`$1')
  {line to rvec_(rp_len/2-csdim_,0)
      {line to rvec_(csdim_,csdim_) \
       then to rvec_(2*csdim_,0)\
       then to rvec_(csdim_,-csdim_) \
       then to Here `$4' }
   ifelse(`$2',I,
    `{arrow from rvec_(csdim_/4,0) \
          to rvec_(csdim_*7/4,0)}',
   `$2',i,
    `{line from rvec_(csdim_,csdim_) \
          to rvec_(csdim_,-csdim_)}',
   `$2',V,
    `{"ifsvg(-,`$-$')" at rvec_(csdim_*0.5,0) ifsvg(+(0,textht/10))}
     {"ifsvg(+,`$+$')" at rvec_(csdim_*1.5,0) ifsvg(+(0,textht/10))}',
   `$2',v,
    `{line to rvec_(2*csdim_,0)} ')
   line from rvec_(2*csdim_,0) \
          to rvec_(rp_len/2+csdim_,0) }
  {[box invis ht_ 2*csdim_ wid_ 2*csdim_] at rvec_(rp_len/2,0)}
  line to rvec_(rp_len,0) invis ')')

                                `battery( linespec, n, R )
                                 Arg 3: reversed polarity'
define(`battery',`ifelse(`$3',R,
 `reversed(`battery',`$1',`$2',,shift(shift(shift($@))))',
 `eleminit_(`$1')
  define(`m4n',`ifelse(`$2',,1,(`$2'))')define(`m4cs',`dimen_/12')dnl
  define(`m4wd',`m4cs*(m4n*2-1)')define(`m4ht',`dimen_/2')dnl
  { line to rvec_(rp_len/2-m4wd/2,0)
    for m4i = 0 to 2*(m4n-1) by 2 do {
      { line from rvec_(m4i*m4cs,m4ht/4) \
        to rvec_(m4i*m4cs,-m4ht/4) }
      { line from rvec_((m4i+1)*m4cs,m4ht/2) \
        to rvec_((m4i+1)*m4cs,-m4ht/2) } }
    line from rvec_(m4wd,0) \
          to rvec_(rp_len/2+m4wd/2,0) }
  {[box invis ht_ m4ht wid_ m4wd] at rvec_(rp_len/2,0)}
  line to rvec_(rp_len,0) invis ')')

                                `ebox(linespec, length, ht, greyvalue)
                                 Box element; length and ht are relative to
                                 the direction of linespec'
define(`ebox',`eleminit_(`$1')
   define(`m4wd',ifelse(`$2',,`dimen_/2',`($2)'))dnl
   define(`m4ht',ifelse(`$3',,`dimen_/5',`($3)'))dnl
   {line to rvec_(max(0,rp_len/2-m4wd/2),0)
    ifelse(`$4',,`lbox(m4wd,m4ht)',`m4fshade(`$4',lbox(m4wd,m4ht))')
    line to rvec_(max(0,rp_len/2-m4wd/2),0)}
  {[box invis ht_ m4ht wid_ m4wd] at rvec_(rp_len/2,0)}
   line to rvec_(rp_len,0) invis ')

                                `fuse( linespec, chars, wid, ht )
                                 chars A|B|C|D|S|HB|HC or dA (=D)'
define(`fuse',`eleminit_(`$1')
  define(`m4fusetype',`ifelse(`$2',,A,`$2',D,dA,`$2')')dnl
  define(`m4ht',ifelse(`$4',,`dimen_/5'ifinstr(`$2',H,*5/3),`($4)'))dnl
  define(`m4d',ifinstr(`$2',H,`m4ht/5',0))dnl
  define(`m4wd',ifelse(`$3',,`m4ht*2',`($3)'))dnl
  {line to rvec_(max(0,rp_len/2-m4wd/2),0)
  sc_draw(`m4fusetype',HB,
   `{move to rvec_(m4d,0); lbox(m4wd-2*m4d,m4ht-2*m4d)}
    {lbox(m4wd,m4ht)}
    line to rvec_(m4wd+max(0,rp_len/2-m4wd/2),0)}')
  sc_draw(`m4fusetype',HC,
   `{move to rvec_(m4d,0); {lbox(m4wd-2*m4d,m4ht-2*m4d)}
    {line from rvec_((m4wd-2*m4d)/5,m4ht/2-m4d) \
            to rvec_((m4wd-2*m4d)/5,-m4ht/2+m4d)}
    line from rvec_((m4wd-2*m4d)*4/5,m4ht/2-m4d) \
            to rvec_((m4wd-2*m4d)*4/5,-m4ht/2+m4d) }
    {lbox(m4wd,m4ht)}
    move to rvec_(m4wd,0); line to rvec_(max(0,rp_len/2-m4wd/2),0)}')
  sc_draw(`m4fusetype',A,
   `arc  cw to rvec_(m4ht,0) rad m4ht/2 with .c at rvec_(m4ht/2,0)dnl
    ifelse(m4a,d,`; {dot(at last arc.start,,1)}')
    arc ccw to rvec_(m4ht,0) rad m4ht/2 with .c at rvec_(m4ht/2,0)
    line to rvec_(max(0,rp_len/2-m4wd/2),0)dnl
    ifelse(m4a,d,`; dot(at last line.start,,1)') }')
  sc_draw(`m4fusetype',B,
   `{lbox(m4wd,m4ht)}
    line to rvec_(m4wd+max(0,rp_len/2-m4wd/2),0)}')
  sc_draw(`m4fusetype',C,
   `{lbox(m4wd,m4ht)}
    {line from rvec_(m4wd/5,-m4ht/2) \
          to rvec_(m4wd/5,m4ht/2)}
    {line from rvec_(m4wd*4/5,-m4ht/2) \
          to rvec_(m4wd*4/5,m4ht/2)}
    move to rvec_(m4wd,0); line to rvec_(max(0,rp_len/2-m4wd/2),0)}')
  sc_draw(`m4fusetype',S,
   `{lbox(m4wd,m4ht)}
    {m4fshade(m4fill,lbox(m4wd/5,m4ht))}
    move to rvec_(m4wd,0); line to rvec_(max(0,rp_len/2-m4wd/2),0)}')
  {[box invis ht_ m4ht wid_ m4wd] at rvec_(rp_len/2,0)}
   line to rvec_(rp_len,0) invis ')

                                `memristor( linespec, wid, ht )'
define(`memristor',`eleminit_(`$1')
  define(`m4ht',ifelse(`$3',,`dimen_/5',`($3)'))define(`m4htx',`m4ht/4')dnl
  define(`m4wd',ifelse(`$2',,`dimen_/2',`($2)'))define(`m4wdx',`m4wd*4/25')dnl
  { line to rvec_(max(0,rp_len/2-m4wd/2),0)
    {[lbox(m4wd,m4ht)] at rvec_(m4wd/2,0)}
    line to rvec_(m4wdx,0) \
       then to rvec_(m4wdx,m4htx) \
       then to rvec_(m4wdx*2,m4htx) \
       then to rvec_(m4wdx*2,-m4htx) \
       then to rvec_(m4wdx*3,-m4htx) \
       then to rvec_(m4wdx*3,m4htx) \
       then to rvec_(m4wdx*4,m4htx) \
       then to rvec_(m4wdx*4,0) \
       then to rvec_(m4wdx*5,0)
    m4fshade(m4fill,lbox(m4wd/4,m4ht))
    line to rvec_(max(0,rp_len/2-m4wd/2),0) }
  line invis to rvec_(rp_len,0)')

                                `heater( linespec, nparts, wid, ht )'
define(`heater',`eleminit_(`$1')
  define(`m4hn',ifelse(`$2',,4,`$2'))dnl
  define(`m4wd',ifelse(`$3',,`dimen_/2',`($3)'))dnl
  define(`m4ht',ifelse(`$4',,`dimen_/5',`($4)'))dnl
  { line to rvec_(max(0,rp_len/2-m4wd/2),0)
    {[lbox(m4wd,m4ht)] at rvec_(m4wd/2,0)}
    for m4ix=1 to m4hn-1 do {
      {line from rvec_(m4ix*m4wd/(m4hn),m4ht/2) \
          to rvec_(m4ix*m4wd/(m4hn),-m4ht/2)}}
    line from rvec_(m4wd,0) \
          to rvec_(max(0,rp_len/2+m4wd/2),0) }
  line invis to rvec_(rp_len,0)')

                                `thermocouple(linespec, wid, ht, L|R)
                                 R=right orientation'
define(`thermocouple',`eleminit_(`$1')
   define(`m4wd',ifelse(`$2',,`dimen_/5',`($2)'))dnl
   define(`m4ht',ifelse(`$3',,`dimen_/2',`($3)'))dnl
   define(`m4ths',`ifinstr(`$4',R,-)')dnl
   {line to rvec_(max(0,rp_len/2-m4wd/2),0) \
    then to rvec_(max(0,rp_len/2-m4wd/2),m4ths`'(m4ht-m4wd/2)) \
    then to rvec_(rp_len/2,m4ths`'m4ht) \
    then to rvec_(max(0,rp_len/2-m4wd/2)+m4wd,m4ths`'(m4ht-m4wd/2)) \
    then to rvec_(max(0,rp_len/2-m4wd/2)+m4wd,0) \
    then to rvec_(rp_len,0)}
  { dot(at rvec_(rp_len/2,m4ths`'m4ht)) }
  {[box invis ht_ m4ht wid_ m4wd] at rvec_(rp_len/2,m4ths`'m4ht/2)}
   line to rvec_(rp_len,0) invis ')

                                `lamp(linespec,[R])'
define(`lamp',`define(`m4ng',ifinstr(`$2',R,-))define(`m4hw',`dimen_/10')dnl
define(`m4dp',(m4ng`'m4hw/2))define(`m4ht',(m4ng`'dimen_/8))dnl
eleminit_(`$1')
 { line to rvec_(rp_len/2-m4hw,0) \
     then to rvec_(rp_len/2-m4hw,m4ng`'dimen_/3.2)
   spline ifdpic(ctension_) to rvec_(0,m4ht) \
      then to rvec_(1.3*m4hw, m4ht) \
      then to rvec_(1.3*m4hw,-m4dp) \
      then to rvec_(0.7*m4hw,-m4dp) \
      then to rvec_(0.7*m4hw, m4ht) \
      then to rvec_(2*m4hw,m4ht) \
      then to rvec_(2*m4hw,0)
   line to rvec_(0,-(m4ng`'dimen_/3.2)) \
      then to rvec_(rp_len/2-m4hw,-(m4ng`'dimen_/3.2)) }
   { [ circle rad dimen_/5 ] at rvec_(rp_len/2,m4ng`'dimen_/3.2) }
   line invis to rvec_(rp_len,0) ')

                                `cbreaker( linespec, L|R, D|T|TS )
                                 circuit breaker to left or right of linespec,
                                 D=with dots; T=thermal; TS=squared thermal'
define(`cbreaker',`ifinstr(`$3',T,
   `tbreaker($@)',
   `mbreaker($@)')')

define(`tbreaker',`eleminit_(`$1') define(`m4ho',0)
 {ifinstr(`$3',TS,
  `define(`m4h',`dimen_/5')define(`m4v',`m4h/2')define(`m4ho',`m4v/2')dnl
   m4j = max(0,rp_len/2-m4h/2)
   line to rvec_(m4j,0) \
    then to rvec_(m4j,ifelse(`$2',R,-)m4h/2) \
    then to rvec_(m4j+m4h,ifelse(`$2',R,-)m4h/2) \
    then to rvec_(m4j+m4h,0) \
    then to rvec_(m4j*2+m4h,0) ',
  `define(`m4h',`dimen_*2/5')define(`m4v',`m4h/2')define(`m4ho',0)dnl
   m4j = max(0,rp_len/2-m4h/2)
   line to rvec_(m4j,0)
   {round
    arc cw to rvec_( m4h/4,0)+vec_(Rect_(m4h/4,-60)) with .c at rvec_( m4h/4,0)}
   move to rvec_(m4h,0)
   {round
    arc cw to rvec_(-m4h/4,0)+vec_(Rect_(m4h/4,120)) with .c at rvec_(-m4h/4,0)}
   line to rvec_(m4j,0)
 ') }
 {[box invis ht_ m4v wid_ m4h ] at rvec_(rp_len/2,ifelse(`$2',R,-)m4ho) }
  line to rvec_(rp_len,0) invis ')

define(`mbreaker',`eleminit_(`$1') define(`m4R',`ifelse(`$2',R,-)')
  define(`m4h',`dimen_/3') define(`m4cr',`((m4h+2*dimen_/32)*5/8)')dnl
  define(`m4ht',`(m4cr-sqrt(m4cr^2-(m4h/2+dimen_/32)^2)+dimen_/16)')dnl
  {line to rvec_(max(0,rp_len/2-m4h/2),0)
  {ifelse(`$3',D,`dot(,,1)
   move to rvec_(0,m4R`'dotrad_);')dnl
   arc ifelse(`$2',R,c)cw from rvec_(-dimen_/32,m4R`'dimen_/16) \
     to rvec_(m4h+dimen_/32,m4R`'dimen_/16) rad m4cr \
     with .c at rvec_(m4h/2,m4R`'(m4ht-m4cr))}
  {line from rvec_(m4h,0) \
          to rvec_(m4h+max(0,rp_len/2-m4h/2),0)
   ifelse(`$3',D,`dot(at last line.start,,1)') }
  [box invis ht_ m4ht ifelse(`$3',D,`+2*dotrad_') wid_ m4h+dimen_/16] \
    at rvec_(m4h/2,m4R`'(m4ht/2)) }
  line to rvec_(rp_len,0) invis ')

                                `gap( linespec,fill,A )
                                 Gap with filled dots e.g.
                                 gap(down_ linewid/2,1); rlabel(+,v_1,-)
                                 A: chopped arrow between dots'
define(`gap',`eleminit_(`$1')
  dot(,,ifelse(`$2',,0,`$2')); dot(at last line.end,,ifelse(`$2',,0,`$2'))
  ifelse(`$3',A,
   `{arrow from last line.start to last line.end chop dotrad_*3}')
  {[box invis ht_ 0 wid_ min(rp_len,(dimen_*4/9+rp_len)/3)] at last line.c}
  ')

                                `arrowline( linespec )
                                 line with midpoint arrowhead
                                 e.g. arrowline(up 1 dotted); llabel(,I_2)'
define(`arrowline',`line ifelse(`$1',,`to rvec_(elen_,0)',`$1')
  { arrow from last line.start to last line.end \
      chop lin_leng(last line)/2-arrowht/2
   [box invis ht_ arrowwid wid_ arrowht] at last line.c }')

                          `ground( at position, T, N|F|S|L|P|E, D|U|L|R|degrees)
                                 T=truncated stem; N=normal ground,
                                 F=frame, S=signal, L=low-noise, P=protective,
                                 E=European;
                                 down (default), up, left, right, angle (deg)'
define(`ground',`box invis ht 0 wid 0 with .c ifelse(`$1',,`at Here',`$1')
  define(`m4v',`dimen_/6')define(`m4h',`dimen_/16')dnl
  {setdir_(ifelse(`$4',,-90,`$4'))
  ifelse(`$2',,`line from last box.c to rvec_(dimen_/4,0)')
  ifelse(`$3',F,
    `{line from rvec_(dimen_/8,m4v-dimen_/12) \
          to rvec_(0,m4v) \
       then to rvec_(0,-m4v) \
       then to rvec_(dimen_/8,-m4v-dimen_/12)}
     line to rvec_(dimen_/8,-dimen_/12)',
  `$3',S,
    `{line to rvec_(0,m4v) \
       then to rvec_(m4v*1.5,0) \
       then to rvec_(0,-m4v) \
       then to Here }',
  `$3',Q,
    `{shade(0,line to rvec_(0,m4v) \
       then to rvec_(m4v*1.5,0) \
       then to rvec_(0,-m4v) \
       then to Here) }',
  `$3',L,
    `{move to rvec_(m4h,0)
      arc cw rad m4v*3/2 from rvec_(Rect_(m4v*3/2,-60)) \
        to rvec_(Rect_(m4v*3/2,60)) with .c at Here}
     ground(,T,,`$4')',
  `$3',P,
    `{Grnd_C: circle rad m4v*3/2 at rvec_(m4h,0)}
     ground(,T,,`$4')',
  `$3',E,
    `{line from rvec_(0,m4v*2/3) \
          to rvec_(0,-m4v*2/3) thick linethick*2}',
  `{line from rvec_(0,m4v) \
          to rvec_(0,-m4v)}
   {line from rvec_(m4h,dimen_/9) \
          to rvec_(m4h,-dimen_/9)}
   line from rvec_(2*m4h,dimen_/14) \
          to rvec_(2*m4h,-dimen_/14)')
   resetdir_} ')

                        `antenna(at position, T, A|L|T|S|D|P|F, U|D|L|R|degrees)
                                 arg2=T: truncate stem
                                 arg3= A=aerial; L=loop, T=triangle, S=diamond,
                                       D=dipole, P=phased, F=fork;
                                 up (default), down, left, right, angle (deg)'
define(`antenna',`[ T: Here
  define(`m4v',`dimen_/2')define(`m4h',`dimen_/12')dnl
  define(`m4atype',ifelse(`$3',,A,`$3'))dnl
  setdir_(ifelse(`$4',,90,`$4'))
  ifelse(
  m4atype,L,
   `T1: rvec_(0,m4h); T2: rvec_(0,-m4h)
    ifelse(`$2',,`move to rvec_(m4h*2,0)')
    line from T1 to rvec_(0,m4h) \
       then to rvec_(0,m4v/2) \
       then to rvec_(m4v-m4h,m4v/2) \
       then to rvec_(m4v-m4h,-m4v/2+m4h) \
       then to rvec_(m4h,-m4v/2+m4h) \
       then to rvec_(m4h,m4v/2-m4h) \
       then to rvec_(m4v,m4v/2-m4h) \
       then to rvec_(m4v,-m4v/2) \
       then to rvec_(0,-m4v/2) \
       then to rvec_(0,-m4h) \
       then to T2',
  m4atype,T,
   `ifelse(`$2',,`move to rvec_(m4h*2,0)')
    line to rvec_(m4v*3/4,m4v*sqrt(3)/4) \
      then to rvec_(m4v*3/4,-m4v*sqrt(3)/4) \
      then to Here
    line from rvec_(m4v*3/4,0) \
        to T',
  m4atype,S,
   `T1: rvec_(0,m4h); T2: rvec_(0,-m4h)
    ifelse(`$2',,`move to rvec_(m4h*2,0)')
    line from T1 to rvec_(0,m4h) \
       then to rvec_(m4v*3/4-m4h,m4v*3/4) \
       then to rvec_(2*m4v*3/4-m4h,0) \
       then to rvec_(m4v*3/4-m4h,-m4v*3/4) \
       then to rvec_(0,-m4h) \
       then to T2',
  m4atype,D,
   `T1: rvec_(0,m4h); T2: rvec_(0,-m4h)
    ifelse(`$2',,`move to rvec_(m4v,0)')
    { line from T1 to rvec_(0,m4h) \
       then to rvec_(0,m4h*3) }
    { line from T2 to rvec_(0,-m4h) \
       then to rvec_(0,-m4h*3) }',
  m4atype,P,
   `ifelse(`$2',,`move to rvec_(m4v*2/3,0)')
    line from T to Here
    { line from rvec_(0,-m4v/3) \
          to rvec_(0,m4v/3) }
    { line from rvec_(m4h,-m4v*2/3) \
          to rvec_(m4h,m4v*2/3) }',
  m4atype,F,
   `ifelse(`$2',,`move to rvec_(m4h*2,0)')
    { line from rvec_(m4v*3/4,m4v*sqrt(3)/4) \
          to rvec_(0,m4v*sqrt(3)/4) \
        then to rvec_(0,-m4v*sqrt(3)/4) \
        then to rvec_(m4v*3/4,-m4v*sqrt(3)/4)}
    line from rvec_(m4v*3/4,0) \
        to T',
  m4atype,A,
  `ifelse(`$2',,`move to rvec_(m4h*2,0)')
   { line from rvec_(m4v*3/4, m4v*sqrt(3)/4) to Here \
       then to rvec_(m4v*3/4,-m4v*sqrt(3)/4) }
   line from rvec_(m4v*3/4,0) \
        to T')
  `$5'; resetdir_ ] with .T ifelse(`$1',,`at Here',`$1')')

                                `switch( linespec,L|R,[O|C][D],L|B|D )
                                 Wrapper for bswitch, lswitch, dswitch
                                 R=right orientation (default L=left)
                                 if arg4=blank or L: arg3 = [O|C][D][K][A]
                                   D=dotted points; K=closed switch;
                                   A=arrowhead on switch blade;
                                   O=opening arrow; C=closing arrow
                                 if arg4=B (button switch): arg3 = O|C
                                   O=normally open; C=normally closed
                                 if arg4=D: arg3 = same as for dswitch'
define(`switch',`ifelse(
 `$4',, `lswitch(`$1',`$2',`$3')',
 `$4',L,`lswitch(`$1',`$2',`$3')',
 `$4',B,`bswitch(`$1',`$2',`$3')',
 `$4',D,`define(`m4qna_',`$3')dnl
  define(`m4rna_',W`'ifinstr(`$2',C,dBK,B)`'m4qna_)dnl
  dswitch(`$1',`$2',m4rna_)')')

                                `bswitch( linespec,L|R,chars ) pushbutton switch
                                 R=right orientation (default L=left)
                                 chars: O= normally open, C=normally closed'
define(`bswitch',`eleminit_(`$1') dnl
 define(`m4h',`dimen_/3') define(`m4cs',`0.069186*dimen_')dnl (2.5pt)
 define(`m4v',`ifelse(`$2',R,-m4cs,m4cs)')define(`dna_',`$3') dnl
 {line to rvec_(rp_len/2-m4h/2,0) chop 0 chop m4cs}
 { Bsw_T1: circle rad m4cs at rvec_(rp_len/2-m4h/2,0); move to last circle
   { Bsw_T2: circle rad m4cs at rvec_(m4h,0) }; ifelse(`$4',,,`{`$4'}')
   sc_draw(`dna_',C,dnl
    `{ line from rvec_(-m4cs,-(m4v)) \
          to rvec_(m4h+m4cs,-(m4v)) }
     { line from rvec_(m4h/2,-(m4v)) \
          to rvec_(m4h/2,m4v*3) }
     {[box invis ht_ 4*m4cs wid_ m4h+2*m4cs] at rvec_(m4h/2,m4v)}',
    `{ line from rvec_(-m4cs,m4v*2.5) \
          to rvec_(m4h+m4cs,m4v*2.5) }
     { line from rvec_(m4h/2,m4v*2.5) \
          to rvec_(m4h/2,m4v*4.5) }
     {[box invis ht_ 5.5*m4cs wid_ m4h+2*m4cs] at rvec_(m4h/2,m4v*1.75)}')
   line from rvec_(m4h,0) \
          to rvec_(m4h/2+rp_len/2,0) chop m4cs chop 0 }
 line to rvec_(rp_len,0) invis ')

                                `lswitch( linespec,L|R,chars ) knife switch
                                 R=right orientation (default L=left)
                                 chars=[O|C][D][K][A]
                                   D=dotted points; K=closed switch;
                                   A=arrowhead on switch blade;
                                   O=opening arrow; C=closing arrow'
define(`lswitch',`eleminit_(`$1') dnl
 define(`m4v',`dimen_/4')define(`m4cs',`dimen_/4*Sin(10)')dnl
 define(`dna_',`$3')define(`m4d',-1)define(`m4k',15)dnl
 m4t1 = arrowht; m4t2 = arrowwid;
 arrowht = dimen_/0.75*0.08; arrowwid = dimen_/0.75*0.053
 {line to rvec_(rp_len/2-dimen_/6,0)
  sc_draw(`dna_',K,`define(`m4k',25)dnl
    {{ifinstr(`$3',A,arrow m4c_l,line) \
     to LCtangent(Here,rvec_(dimen_/3,0),dotrad_,`$2') chop 0 chop -dotrad_}
     line from rvec_(dimen_/3,0) to rvec_(dimen_/3,ifelse(`$2',R,-)dotrad_)}',
   `{ifinstr(`$3',A,arrow m4c_l,line) \
      to rvec_(dimen_/4,ifelse(`$2',R,-)dimen_/4)}')
  sc_draw(`dna_',D,`dot(,,1) define(`m4d',1)')
  sc_draw(`dna_',C,`{ arc <- m4c_l ifelse(`$2',R,,`c')cw \
      from rvec_(Rect_(dimen_/4,ifelse(`$2',R,,-)m4k))\
      to rvec_(Rect_(dimen_/4,ifelse(`$2',R,-)60)) \
      with .c at rvec_(Rect_(-dimen_/4,ifelse(`$2',R,-)(60-m4k)/2)) }')
  sc_draw(`dna_',O, `{ arc -> m4c_l ifelse(`$2',R,,`c')cw \
      from rvec_(Rect_(dimen_/4,ifelse(`$2',R,,-)10))\
      to rvec_(Rect_(dimen_/4,ifelse(`$2',R,-)75)) \
      with .c at rvec_(Rect_(-dimen_/4,ifelse(`$2',R,-)(75-10)/2)) }') }
 { line from rvec_(rp_len/2+dimen_/6,0) \
          to rvec_(rp_len,0)
   ifelse(m4d,-1,,`dot(at last line.start,,1)') }
 { [box invis ht_ dimen_/4+m4cs wid_ dimen_/3] \
     with .c at rvec_(rp_len/2,ifelse(`$2',R,-)(m4v-(m4cs))/2)}
 arrowht = m4t1 ; arrowwid = m4t2;  ifelse(`$4',,,`{`$4'}')
 line to rvec_(rp_len,0) invis ')

                                `dswitch(linespec,R,W[ud]B[K] chars)
                                 Comprehensive IEEE-IEC single-pole switch:
                                 arg2=R: orient to the right of drawing dir
                                 arg 3:
                                   blank means WB by default
                                   W=baseline
                                   B=contact blade
                                   Bo=contact blade more widely open
                                   dB=contact blade to the right of direction
                                   K=vertical closing contact line
                                     use WdBK for a normally-closed switch

                                   C = external operating mechanism
                                   D = circle at contact and hinge (dD = hinge
                                       only, uD = contact only)
                                   E = emergency button
                                   EL = early close (or late open)
                                   LE = late close (or early open)
                                   F = fused
                                   H = time delay closing
                                   uH = time delay opening
                                   HH = time delay opening and closing
                                   K = vertical closing contact
                                   L = limit
                                   M = maintained (latched)
                                   MM = momentary contact on make
                                   MR = momentary contact on release
                                   MMR = momentary contact on make and release
                                   O = hand operation button
                                   P = pushbutton
                                   R = time-delay operating arm
                                   T = thermal control linkage
                                   Y = pull switch
                                   Z = turn switch'
define(`dswitch',`eleminit_(`$1')
define(`dna_',ifelse(`$3',,WB,`$3'))dnl
define(`m4R',`ifelse(`$2',R,-)')define(`m4sc',`dimen_/24')dnl
 tr_xy_init(last line.c,m4sc,m4R)
 M4T: M4_xyO; M4B: M4T
 { line to tr_xy(-4,0)
   line from tr_xy(4,0) \
        to 2nd last line.end
  sc_draw(`dna_',Bo,
   `define(`m4c',ifelse(m4a,d,-))dnl
    M4B: line from tr_xy(-4,0) \
          to tr_xy(4,m4c`'13/sqrt(3))
    M4Q: 2 between M4_xyO and M4B.c')
  sc_draw(`dna_',B,
   `define(`m4c',ifelse(m4a,d,-))dnl
    M4B: line from tr_xy(-4,0) \
          to tr_xy(5.5,m4c`'4)
    M4Q: 2 between M4_xyO and M4B.c')
  sc_draw(`dna_',MMR,
   `line from tr_xy(6,1.16) \
          to tr_xy(4,0) \
       then to tr_xy(6,-1.16)')
  sc_draw(`dna_',MM,
   `line from tr_xy(5,0) \
          to tr_xy(4,0) \
       then to tr_xy(6,1.16)')
  sc_draw(`dna_',MR,
   `line from tr_xy(5,0) \
          to tr_xy(4,0) \
       then to tr_xy(6,-1.16)')
  sc_draw(`dna_',D,
   `ifelse(m4a,u,,`dot(at tr_xy(-4,0),,1)')
    ifelse(m4a,d,,`dot(at tr_xy(4,0),,1)')')
  sc_draw(`dna_',EL,
   `line from 0.99 along_(M4B) \
        to M4B.end \
      then to M4B.end + ta_xy(vperp(M4B,m4c`'2.5,R))')
  sc_draw(`dna_',LE,
   `line from 0.99 along_(M4B) \
        to M4B.end \
      then to M4B.end + ta_xy(vperp(M4B,m4c`'2.5))')
  sc_draw(`dna_',K,
   `line from tr_xy(4,0) \
          to tr_xy(4,m4c`'5)')
  sc_draw(`dna_',F,
   `M4dT: 3/16 along_(M4B); M4dQ: 11/16 along_(M4B)
    line from M4dT to M4dT + ta_xy(neg_(m4c)1/2,1) \
      then to M4dQ + ta_xy(neg_(m4c)1/2,1) \
      then to M4dQ + ta_xy(m4c`'1/2,-1) \
      then to M4dT + ta_xy(m4c`'1/2,-1) \
      then to M4dT ')
  sc_draw(`dna_',L,
   `M4dT: 11/16 along_(M4B) define(`m4e',ifelse(m4a,d,-))
    line from 5/16 along_(M4B) \
      to M4dT + ta_xy(neg_(m4e)1,ifelse(m4c,m4e,,-)2) \
      then to M4dT')
  sc_draw(`dna_',T,
   `define(`m4t',ifelse(m4a,d,-))dnl
    M4T: M4B.c+ta_xy(0,m4t`'12)
    line from M4B.c to M4B.c+ta_xy(0,m4t`'4.5) \
       then to M4B.c+ta_xy(3,m4t`'4.5) \
       then to M4B.c+ta_xy(3,m4t`'7.5) \
       then to M4B.c+ta_xy(0,m4t`'7.5) \
       then to M4T ')
  sc_draw(`dna_',M,
   `define(`m4t',ifelse(m4a,d,-))dnl
    M4T: M4B.c+ta_xy(0,m4t`'12)
    line dashed 1.5*m4sc from M4B.c to M4B.c+ta_xy(0,m4t`'4.5)
    line to M4B.c+ta_xy(-3,m4t`'6) \
       then to M4B.c+ta_xy(0,m4t`'7.5)
    line dashed 1.5*m4sc to M4T ')
  sc_draw(`dna_',C,
   `M4T: M4B.c+ta_xy(0,ifelse(m4a,d,-)12)
    line dashed from M4B.c to M4T ')
  sc_draw(`dna_',O,
   `line from M4T + ta_xy(-2.5,0) \
        to M4T + ta_xy(2.5,0) ')
  sc_draw(`dna_',P,
   `line from M4T + ta_xy(-2.5,-2.5) \
        to M4T + ta_xy(-2.5,0) \
      then to M4T + ta_xy(2.5,0) \
      then to M4T + ta_xy(2.5,-2.5) ')
  sc_draw(`dna_',Y,
   `line from M4T + ta_xy(-2.5,2.5) \
        to M4T + ta_xy(-2.5,0) \
      then to M4T + ta_xy(2.5,0) \
      then to M4T + ta_xy(2.5,2.5) ')
  sc_draw(`dna_',Z,
   `line from M4T + ta_xy(-2.5,-2.5) \
        to M4T + ta_xy(-2.5,0) \
      then to M4T + ta_xy(2.5,0) \
      then to M4T + ta_xy(2.5,2.5) ')
  sc_draw(`dna_',R,
   `define(`m4t',ifelse(m4a,d,-))dnl
    M4dT: 5/12 along_(M4B); M4dQ: 7/12 along_(M4B)
    line from M4dT to M4dT + ta_xy(0,m4t`'12)
    line from M4dQ to M4dQ + ta_xy(0,m4t`'(neg_(m4c)sqrt(3)/2+12))
    M4T: 1/2 between Here and 2nd last line.end ')
  sc_draw(`dna_',HH,
   `arc ifelse(m4R,-,c)cw \
      from M4T+ta_xy(3,3/2) \
        to M4T+ta_xy(-3,3/2) with .c at M4T+ta_xy(0,4.0)
    arc ifelse(m4R,,c)cw \
      from M4T+ta_xy(3,-3/2) \
        to M4T+ta_xy(-3,-3/2) \
      with .c at M4T+ta_xy(0,-4.0) ')
  sc_draw(`dna_',H,
   `define(`m4t',ifelse(m4a,d,-))dnl
    arc ifelse(m4t,m4R,,c)cw \
      from M4T+ta_xy(3,m4t`'3/2) \
        to M4T+ta_xy(-3,m4t`'3/2) \
      with .c at M4T + ta_xy(0,m4t`'4.0) ')
  sc_draw(`dna_',E,
   `line from M4T + ta_xy(-2.5,0) \
        to M4T + ta_xy(2.5,0)
    arc ifelse(m4R,-,,c)cw to last line.start with .c at M4T + ta_xy(0,-1.5) ')
    M4dQ: M4Q - (M4_xyO.x,M4_xyO.y)
  M4dT: M4T - (M4_xyO.x,M4_xyO.y)
  if M4dQ.x*M4dT.x + M4dQ.y*M4dT.y > 0 then { M4Q: M4_xyO }
  [ box invis ht_ distance(M4T,M4Q) wid_ 8*m4sc ] \
      with .c at 0.5 between M4T and M4Q
 }
 line to rvec_(rp_len,0) invis ')

                                `Amplifier amp( linespec,size )'
define(`amp',`eleminit_(`$1') define(`m4wd',`ifelse(`$2',,`dimen_',`($2)')')dnl
 {line to rvec_(max(0,rp_len/2-m4wd/2),0)
   line from rvec_(m4wd,0) \
          to rvec_(0,m4wd/2) \
       then to rvec_(0,-m4wd/2) \
       then to rvec_(m4wd,0) \
       then to rvec_(max(m4wd,rp_len/2+m4wd/2),0) }
 {[box invis ht_ m4wd wid_ m4wd] at rvec_(max(m4wd,rp_len)/2,0)}
 line to rvec_(max(rp_len,m4wd),0) invis ')

                                `integrator( linespec,size )'
define(`integrator',`eleminit_(`$1')
 define(`m4wd',`ifelse(`$2',,`dimen_',`($2)')')dnl
 {line from rvec_(m4wd/4,m4wd/2) \
          to rvec_(0,m4wd/2) \
       then to rvec_(0,-m4wd/2) \
       then to rvec_(m4wd/4,-m4wd/2) }
 {line from rvec_(m4wd*5/4,0) \
          to rvec_(m4wd/4,m4wd/2) \
    then to rvec_(m4wd/4,-m4wd/2) \
    then to rvec_(m4wd*5/4,0) \
    then to rvec_(max(rp_len,m4wd*5/4),0) }
 { [box invis ht_ m4wd wid_ m4wd*5/4] at rvec_(m4wd*5/8,0) }
 line to rvec_(max(rp_len,m4wd*5/4),0) invis ')

                                `opamp(linespec,
                                  - label, + label, size, chars)
                                   drawn as a []:
                                   defined positions:
                                     W, N, E, S, Out, E1, E1, In1, In2
                                   chars:
                                     P: power connections V1,V2
                                     R: labels at In1,In2 swapped
                                     T: truncated point '
define(`opamp',
`[define(`m4v',`ifelse(`$4',,`dimen_',`($4)')')define(`m4h',`m4v')dnl
define(`dna_',`$5')dnl
  eleminit_(`$1',max(elen_-m4h/4,m4h))
 W: Here
 N: vec_(0,m4v/2)
 S: vec_(0,-m4v/2)
 E: vec_(m4h,0)
 C: vec_(m4h/2,0)
 { sc_draw(`dna_',T,
    `line to N then to 0.75 between N and E \
       then to 0.75 between S and E then to S then to W
     line from 0.75 between W and E to E',
    `line to N then to E then to S then to W; move to E')
   if rp_len > m4h then { line to rvec_(rp_len-m4h,0) }
 Out: Here }
 E1: vec_(m4h/2,m4v/4)
 E2: vec_(m4h/2,-m4v/4)
 In1: vec_(0,m4v/4)
 In2: vec_(0,-m4v/4)
   { move to In`'ifinstr(dna_,R,2,1)
     ifelse(`$2',,"ifsvg(-,`{\scriptsize$-$}')" \
       at rvec_(4pt__,0) ifsvg(+(0,textht/10)),m4lstring(`$2',"`$2'"))}
   { move to In`'ifinstr(dna_,R,1,2)
     ifelse(`$3',,"ifsvg(+,`{\scriptsize$+$}')" \
       at rvec_(4pt__,0) ifsvg(+(0,textht/10)),m4lstring(`$3',"`$3'"))}
 sc_draw(`dna_',P,
   `{line from E1 to (vec_(m4h/2,m4v/4+m4v/8));    V1: Here}
    {line from E2 to (vec_(m4h/2,-(m4v/4+m4v/8))); V2: Here}')
 `$6' ] ')

                                `dac(width,height,nIn,nN,nOut,nS)'
define(`dac',`[
  define(`dac_ht',`ifelse(`$2',,(dimen_),`$2')')dnl
  define(`dac_wd',`ifelse(`$1',,(dimen_+dac_ht/2),`$1')')dnl
In: Here
C:  rvec_((dac_wd-dac_ht/2)/2,0)
NE: rvec_(dac_wd-dac_ht/2, dac_ht/2)
Out:rvec_(dac_wd,0)
SE: rvec_(dac_wd-dac_ht/2,-dac_ht/2)
NW: rvec_(0,dac_ht/2)
SW: rvec_(0,-dac_ht/2)
  define(`m4dn',ifelse(`$3',,1,`eval($3)'))dnl
  for_(1,m4dn,1,`In`'m4x: NW-vec_(0,dac_ht*(2*m4x-1)/(2*m4dn))')dnl
  define(`m4dn',ifelse(`$4',,1,`eval($4)'))dnl
  for_(1,m4dn,1,`N`'m4x: NW+vec_((dac_wd-dac_ht/2)*m4x/(m4dn+1),0)')dnl
  define(`m4dn',ifelse(`$5',,1,`eval($5)'))dnl
  for_(1,m4dn,1,`r = eval(2*m4x-1)/eval(m4dn*2)
    Out`'m4x: Out-vec_(ifelse(eval((2*m4x-1)<m4dn),1,,-)dac_ht*(0.5-r),
      dac_ht*(0.5-r))')dnl
  define(`m4dn',ifelse(`$6',,1,`eval($6)'))dnl
  for_(1,m4dn,1,`S`'m4x: SW+vec_((dac_wd-dac_ht/2)*m4x/(m4dn+1),0)')dnl
  line to NW then to NE then to Out then to SE then to SW then to Here
  `$7']')

                                `adc(width,height,nIn,nN,nOut,nS)'
define(`adc',`[
  define(`adc_ht',`ifelse(`$2',,(dimen_),`$2')')dnl
  define(`adc_wd',`ifelse(`$1',,(dimen_+adc_ht/2),`$1')')dnl
In: Here
C:  rvec_(adc_ht/4+adc_wd/2,0)
NE: rvec_(adc_wd, adc_ht/2)
Out:rvec_(adc_wd,0)
SE: rvec_(adc_wd,-adc_ht/2)
NW: rvec_(adc_ht/2, adc_ht/2)
SW: rvec_(adc_ht/2,-adc_ht/2)
  define(`m4dn',ifelse(`$3',,1,`eval($3)'))dnl
  for_(1,m4dn,1,`r = eval(2*m4x-1)/eval(m4dn*2)
    In`'m4x: In+vec_(ifelse(eval((2*m4x-1)<m4dn),1,,-)adc_ht*(0.5-r),
      adc_ht*(0.5-r))')dnl
  define(`m4dn',ifelse(`$4',,1,`eval($4)'))dnl
  for_(1,m4dn,1,`N`'m4x: NW+vec_((adc_wd-adc_ht/2)*m4x/(m4dn+1),0)')dnl
  define(`m4dn',ifelse(`$5',,1,`eval($5)'))dnl
  for_(1,m4dn,1,`Out`'m4x: NE-vec_(0,adc_ht*(2*m4x-1)/(2*m4dn))')dnl
  define(`m4dn',ifelse(`$6',,1,`eval($6)'))dnl
  for_(1,m4dn,1,`S`'m4x: SW+vec_((adc_wd-adc_ht/2)*m4x/(m4dn+1),0)')dnl
  line from Out to SE then to SW then to In then to NW then to NE then to Out
  `$7']')

                               `diode(linespec,
                                 B|CR|D|F|G|L|LE[R]|P[R]|S|Sh|T|V|v|w|Z|chars,
                                 [R][E])
                                 Adding K to arg2 draws open arrowheads
                                 Arg 3: R=reversed polarity, E=enclosure'
define(`diode',
`define(`m4dtype',`$3')sc_draw(`m4dtype',R,
 `reversed(`diode',`$1',`$2',m4dtype,shift(shift(shift($@))))',
 `eleminit_(`$1')dnl
  define(`dma_',`$2') ifelse(dma_,K,,
   `sc_draw(`dma_',K,`define(`m4ahd')',`define(`m4ahd',f)')')dnl
  ifelse(dma_,, `m4gen_d(LACR,m4ahd)',
         dma_,B,`m4gen_d(uLAZQuR,m4ahd)define(`m4dh',2*m4dh)',
         dma_,CR,`m4gen_d(LACRrb,m4ahd)',
         dma_,D,`m4gen_d(LuAHdQR,m4ahd)define(`m4dv',2*m4dv)',
         dma_,F,`m4gen_d(LFR,m4ahd)',
         dma_,G,`m4gen_d(uLAQuR,m4ahd)define(`m4dh',2*m4dh)',
         dma_,K,`m4gen_d(LACR)',
         dma_,L,`m4gen_d(LAcCR)',
         dma_,LE,`m4gen_d(LuEACR,m4ahd)',
         dma_,LER,`m4gen_d(LdEACR,m4ahd)',
         dma_,P,`m4gen_d(LuPACR,m4ahd)',
         dma_,PR,`m4gen_d(LdPACR,m4ahd)',
         dma_,S,`m4gen_d(LASR,m4ahd)',
         dma_,Sh,`m4gen_d(LFcCR,)',
         dma_,T,`m4gen_d(LATR,m4ahd)',
         dma_,V,`m4gen_d(LACXdR,m4ahd)',
         dma_,v,`m4gen_d(LACvdR,m4ahd)',
         dma_,w,`m4gen_d(LAdvXdR,m4ahd)',
         dma_,Z,`m4gen_d(LAZR,m4ahd)',
         `m4gen_d(patsubst(dma_,f),xtract(dma_,f,R,E))')
  sc_draw(`m4dtype',E,`define(`m4dh',`dimen_*0.7')define(`m4dv',`m4dh')dnl
    { Diode_Env: circle diam m4dh at rvec_(rp_len/2,0) }')
  define(`m4dm',
   `ifelse(dma_,S,`m4dv/4',
           dma_,Z,`(m4dv/4-linethick pt__/2)',
           dma_,v,`m4dv/4',
           dma_,w,`m4dv/4',
                  0)')dnl
 { [ box invis ht_ m4dv+linethick pt__*sqrt(3) wid_ m4dh+linethick pt__ + m4dm
     ] at rvec_(rp_len/2+m4dm/2,0) }
 line invis to rvec_(rp_len,0)')')

                               `m4gen_d(chars,[f][R][E]):
                                *This is an internal macro, subject to change*
                                *General: [u|d] for shift, R for orientation*
                                [u|d]A[c] arrowhead shifted up, down, or 0
                                [u|d]F[c] arrowhead open-sided (Shockley)
                                [u|d]B bar (gate) at arrowhead centre
                                [u|d]BB long bar (gate) at arrowhead centre
                                C vertical bar at right of arrowhead
                                [u|d]E em_arrows out
                                [u|d]F half arrowhead shifted
                                G gate for scr(,B), label G
                                rb current regulator bars
                                H double-length vertical bars
                                [u]L  left stem, uL = shortened
                                N thyristor gate at anode, label Ga
                                [u|d]P em_arrows
                                [u|d]Q[c] shifted left arrowhead [centerline]
                                [u]R  right stem, uR = shortened
                                S S-shape vertical bar
                                T T-diode vertical bar
                                W Thyristor gate from cathode, label G
                                X varicap diode-capacitor
                                [u|d]v varicap diode-capacitor curved plate
                                Y bilateral core
                                Z zener bar
                               arg 2: f= fill the arrowhead
                                      R=right orientation
                                      E=envelope flag '
define(`m4gen_d',`{dnl
  define(`m4dv',`dimen_/6')define(`m4dh',sqrt(3)*m4dv/2)dnl
  define(`ddna_',`ifelse(`$1',,`LACR',`$1')')dnl
  define(`ddf_',`ifelse(`$1',,f,`$2')')dnl
  define(`m4tR',`ifinstr(`$2',R,(-1),1)')dnl
  define(`m4dy',`(linethick pt__)*(sqrt(3)-1)/2')dnl
  M4_s: last line.start; M4_e: last line.end
  sc_draw(`ddna_',L,dnl            left stem, uL = shortened
   `line from M4_s to 0.5 between M4_s and M4_e \
      chop 0 chop m4dh`'ifelse(m4a,,/2)')
  dnl                              Elements drawn from left of body
  sc_draw(`ddna_',E,dnl            EM radiation arrows pointing out
   `ifelse(m4a,d,
     `{em_arrows(,rp_ang*rtod_-135) with .Tail at rvec_(-m4dh*0.3,-m4dv*0.8)}',
     `{em_arrows(,rp_ang*rtod_+135) with .Tail at rvec_(-m4dh*0.3,m4dv*0.8)}')')
  sc_draw(`ddna_',P,dnl            EM radiation arrows
   `ifelse(m4a,d,
     `{em_arrows(,rp_ang*rtod_+45) with .Head at rvec_(-m4dh*0.3,-m4dv*0.8)}',
     `{em_arrows(,rp_ang*rtod_-45) with .Head at rvec_(-m4dh*0.3, m4dv*0.8)}')')
  sc_draw(`ddna_',G,dnl            SCR gate
   `{Gm: line to ifinstr(`$2',E,2,3/2) between Here and \
     rvec_(m4dh,ifelse(m4a,d,-)m4dv/2) ifinstr(`$2',E,`then to \
       rvec_(m4dh*2,ifelse(m4a,d,-)sqrt((4*dimen_/10)^2-(m4dh*2)^2))')
     G: Here}')
  sc_draw(`ddna_',F,dnl            half arrowhead shifted up, down, or 0
   `sc_draw(`ddna_',Fc,`define(`m4Fc')')sc_draw(`ddna_',F,`undefine(`m4Fc')')dnl
    define(`m4dn',`ifelse(m4a,u,m4dv/2,m4a,d,-m4dv/2,0)')
    define(`m4dFline',`Gm: line from rvec_(0,m4tR*m4dn) \
           to rvec_(0,m4tR*(m4dn+m4dv/2)) \
      then to rvec_(m4dh-linethick pt__/2,m4tR*m4dn) \
      then to rvec_(0,m4tR*m4dn)')
    { ifinstr(ddf_,f,`m4fshade(m4fill,m4dFline)',`m4dFline')
    line to ifinstr(`$2',E,
     `rvec_(0,-(m4tR*sqrt((dimen_*0.7/2)^2-(m4dh/2)^2)))',
     `rvec_(0,-(m4tR*m4dv/2))')
     G: Here }
    ifdef(`m4Fc',`{line from rvec_(0,m4tR*m4dn) to rvec_(m4dh,m4tR*m4dn)}')
    move to rvec_(m4dh,0) ')
  ifinstr(ddna_,A,dnl              Arrowhead shifted up, down, or 0
   `sc_draw(`ddna_',Ac,`define(`m4Ac')')sc_draw(`ddna_',A,`undefine(`m4Ac')')dnl
    define(`m4dn',`ifelse(m4a,u,m4dv/2,m4a,d,-m4dv/2,0)')dnl
    define(`m4dFline',`line from rvec_(0,m4dn) \
             to rvec_(0,m4dn+m4dv/2) \
        then to rvec_(m4dh-linethick pt__/2,m4dn) \
        then to rvec_(0,m4dn-m4dv/2) \
        then to rvec_(0,m4dn)')
    { ifinstr(ddf_,f,`m4fshade(m4fill,m4dFline)',`m4dFline')}
    ifdef(`m4Ac',`{line from rvec_(0,m4dn) to rvec_(m4dh,m4dn)}')
    move to rvec_(m4dh,0) ')
  sc_draw(`ddna_',B,dnl            Perp bar at arrowhead centre
   `{ifelse(m4a,u,dnl              from arrow edge or across the centre line
     `Gm: line from        rvec_(-m4dh/2, m4dv/4) \
        to ifinstr(`$2',E,`rvec_(-m4dh/2, dimen_*0.35)',
                          `rvec_(-m4dh/2, m4dv*5/4+m4dy)')',
     m4a,d,
     `Gm: line from        rvec_(-m4dh/2,-m4dv/4) \
        to ifinstr(`$2',E,`rvec_(-m4dh/2,-dimen_*0.35)',
                          `rvec_(-m4dh/2,-m4dv*5/4-m4dy)')',
     `Gm: line from rvec_(-m4dh/2,-m4dv/2-m4dy) \
                 to rvec_(-m4dh/2, m4dv/2+m4dy)
      G: Gm.c')
     ifelse(m4a,,,G: last line.end) }')
  sc_draw(`ddna_',C,dnl            Vertical bar
   `{line from rvec_(0,-m4dv/2-m4dy) \
            to rvec_(0, m4dv/2+m4dy)}')
  m4gen_d2($@)dnl
  m4gen_d3($@)dnl
}') dnl              macro split to keep within m4 buffer size
  define(`m4gen_d2',`dnl
  dnl                             Elements drawn at right of body
  sc_draw(`ddna_',rb,dnl            Current regulator bars
   `{line from rvec_(-m4dv/4,-m4dv/2-m4dy) \
            to rvec_( m4dv/4,-m4dv/2-m4dy)}
    {line from rvec_(-m4dv/4,m4dv/2+m4dy) \
            to rvec_( m4dv/4,m4dv/2+m4dy)}')
  sc_draw(`ddna_',H,dnl            Double length double vertical bars
   `{line from rvec_(0,-m4dv-m4dy) \
            to rvec_(0, m4dv+m4dy)}
    {line from rvec_(-m4dh,-m4dv-m4dy) \
            to rvec_(-m4dh, m4dv+m4dy)}
    move to rvec_(-m4dh,0)')
  sc_draw(`ddna_',N,dnl            thyristor gate at anode, label Ga
   `{Gam: line from rvec_(-m4dh,-m4tR*m4dv/4) \
       to rvec_(-m4dh*2,-m4tR*m4dv*3/4) ifinstr(`$2',E,`then to \
       rvec_(-m4dh*2,-m4tR*sqrt((dimen_*0.7/2)^2-(m4dh*3/2)^2))')
     Ga: Here}')
  sc_draw(`ddna_',S,dnl            S-shape vertical bar
   `{line from rvec_(-m4dv/4,-m4dv/3) \
            to rvec_(-m4dv/4,-m4dv/2-m4dy) \
       then to rvec_(0,-m4dv/2-m4dy) \
       then to rvec_(0, m4dv/2+m4dy) \
       then to rvec_(m4dv/4,m4dv/2+m4dy) \
       then to rvec_(m4dv/4,m4dv/3)}')
  sc_draw(`ddna_',T,dnl            T-diode vertical bar
   `{line from rvec_(-m4dv/4,-m4dv/2-m4dy) \
            to rvec_(0,-m4dv/2-m4dy) \
       then to rvec_(0, m4dv/2+m4dy) \
       then to rvec_(-m4dv/4,m4dv/2+m4dy)}')
  sc_draw(`ddna_',v,dnl            Variable capacitor curved plate
   `ifelse(m4a,d,`define(`m4drad',`sqrt((m4dv/2+m4dy)^2+(m4dv)^2*3/4)')dnl
      {arc cw from rvec_(-(m4drad-m4dv*sqrt(3)/2), m4dv/2+m4dy) \
                to rvec_(-(m4drad-m4dv*sqrt(3)/2),-m4dv/2-m4dy) \
       with .c at rvec_(-m4drad,0)}',
     `{arc cw from rvec_(m4dv/3,-m4dv/2-m4dy) \
                to rvec_(m4dv/3, m4dv/2+m4dy) \
       with .c at rvec_(m4dv/3+m4dv*sqrt(3)/2,0)}
      {line from rvec_(m4dv/3+m4dv*sqrt(3)/2-last arc.rad,0) \
            to rvec_(m4dv/4,0)}')')
  sc_draw(`ddna_',W,dnl            cathode gate
   `{Gm: line from rvec_(0,m4tR*m4dv/4) \
       to rvec_(m4dh,m4tR*m4dv*3/4) ifinstr(`$2',E,
        `then to rvec_(m4dh,\
        m4tR*sqrt((dimen_*0.7/2)^2-(m4dh*3/2)^2))')
     G: Here}')
  sc_draw(`ddna_',X,dnl            Variable capacitor plate
   `{line from rvec_(m4dv/4,-m4dv/2-m4dy) \
            to rvec_(m4dv/4, m4dv/2+m4dy)}')
  sc_draw(`ddna_',Z,dnl            Zener bar
   `{line from rvec_(-m4dv/4,-m4dv/2-m4dy) \
            to rvec_(0,-m4dv/2-m4dy) \
       then to rvec_(0, m4dv/2+m4dy) \
       then to rvec_(m4dv/4,m4dv/2+m4dy)}')
  ifinstr(ddna_,Q,dnl              left arrowhead
   `sc_draw(`ddna_',Qc,`define(`m4Qc')')sc_draw(`ddna_',Q,`undefine(`m4Qc')')dnl
    define(`m4dn',`ifelse(m4a,u,m4dv/2,m4a,d,-m4dv/2,0)')dnl
    {move to rvec_(m4dh,0)
    define(`m4dFline',`line from rvec_(0,m4dn) \
             to rvec_(0,m4dn+m4dv/2) \
        then to rvec_(-(m4dh-linethick pt__/2),m4dn) \
        then to rvec_(0,m4dn-m4dv/2) \
        then to rvec_(0,m4dn) ')
    ifinstr(ddf_,f,`m4fshade(m4fill,m4dFline)',`m4dFline')}
    ifdef(`m4Qc',`{line from rvec_(0,m4dn) \
      to rvec_(-(m4dh-linethick pt__/2),m4dn)}')
    move to rvec_(m4dh,0)')dnl
') dnl              macro split to keep within m4 buffer size
  define(`m4gen_d3',`dnl
  sc_draw(`ddna_',Y,dnl            Bilateral switch
   `define(`m4vt',`(m4tR*m4dv/2)')dnl
      line from rvec_(0,-m4vt) to Here
      define(`m4dFline',`line to rvec_(0,m4vt) \
        then to rvec_(2*m4dh,0) \
        then to rvec_(2*m4dh,-m4vt) then to Here ')
      ifinstr(ddf_,f,`m4fshade(m4fill,m4dFline)',`m4dFline')
      line from rvec_(2*m4dh,m4vt) to rvec_(2*m4dh,0)
      { Gm: line from rvec_(-m4dh,m4vt) \
          to ifinstr(`$2',E,`rvec_(-m4dh,-m4tR*dimen_*0.35)',
                            `rvec_(-m4dh,-m4tR*m4dv*5/4)')
        G: Here }')
  sc_draw(`ddna_',R,dnl            right stem, uR = shortened
   `line from 0.5 between M4_s and M4_e to M4_e \
      chop m4dh ifelse(m4a,,/2,m4a,d,/2+m4dv/4) chop 0')
  ')dnl

                                `em_arrows( type,degrees,length)
                                 type=[N|I|E][D]  N=nonionizing, I=ionizing,
                                 E=simple; D=dot on arrow stem
                                 degrees = absolute arrow direction'
define(`em_arrows',`[ define(`m4dnm_',`ifelse($1,,N,$1)')dnl
  arrowhead = em_arrowhead
  define(`m4_len',
   `ifelse(`$3',,`dimen_*ifinstr(`$1',E,0.25,0.46)',`($3)')')
  ang = ifelse(`$2',,135,`($2)')*dtor_
  sc_draw(`m4dnm_',N,
   `{ A1: arrow m4c_l to rrot_(m4_len,0,ang) wid em_arrowwid ht em_arrowht }
    move to rrot_(0,-em_arrowwid*9/8,ang)
    { A2: arrow m4c_l to rrot_(m4_len,0,ang) wid em_arrowwid ht em_arrowht } ')
  sc_draw(`m4dnm_',I,`m4_rad_arr(A1)
    move to rrot_(0,-em_arrowwid*9/8,ang); m4_rad_arr(A2)')
  sc_draw(`m4dnm_',E,
   `{ A1: line to rrot_(m4_len,0,ang) \
        then to rrot_(m4_len-dimen_/18,dimen_/18,ang) }
    move to rrot_(0,-dimen_/8,ang)
    { A2: line to rrot_(m4_len,0,ang) \
        then to rrot_(m4_len-dimen_/18,dimen_/18,ang) }')
  sc_draw(`m4dnm_',D,`dot(at A1.start); dot(at A2.start)')
  Tail: 0.5 between A1.start and A2.start
  Head: 0.5 between A1.end and A2.end
  `$4']')
define(`m4_rad_arr',`{{`$1': line invis to rrot_(m4_len,0,ang)}
  for_(1,3,1,
   `arc ifelse(m4x,2,c)cw to rrot_(dimen_/10,0,ang) \
      with .c at rrot_(dimen_/20,0,ang)')
    arrow m4c_l to `$1'.end wid em_arrowwid ht em_arrowht*3/4 }')

                                `thyristor(linespec,
                                   [SCR|SCS|SUS|SBS|IEC][chars])
                                 Composite element in [ ] block
                                   SCR: silicon controlled rectifier (default)
                                   SCS: silicon controlled switch
                                   SUS: silicon unilateral switch
                                   SBS: silicon bilateral switch
                                   IEC: type IEC
                                 chars:
                                   A: arrowhead
                                   F: half arrowhead
                                   B: bidirectional diode
                                   E: adds envelope
                                   H: perpendicular gate, endpoint G
                                   N: anode gate, endpoint Ga
                                   R=right orientation
                                   U: centre line in diodes
                                   V: perpendicular gate at arrowhead centre
                                   K: use open arrowheads'
define(`thyristor',
 `define(`m4tharg',ifelse(`$2',,SCR,`$2')) dnl                        default
  define(`m4thtype',xtract(m4tharg,SCR,SCS,SUS,SBS,IEC))dnl
  ifelse(m4thtype,,`define(`m4thtype',xtract(m4tharg,B))')dnl
  define(`m4thx',`patsubst(m4tharg,m4thtype)')dnl        delete the type code
  sc_draw(`m4thx',R,`define(`m4thf',R)',`define(`m4thf')')dnl     orientation
  sc_draw(`m4thx',E,`define(`m4thf',m4thf`'E)')dnl                   envelope
  define(`m4thAc',xtract(m4thx,F,A))define(`m4thAc',patsubst(m4thAc,F,Fc))dnl
  define(`m4thAc',ifelse(m4thAc,,A,m4thAc)`'ifinstr(m4thx,U,c))dnl centerline
  define(`m4thf',m4thf`'ifinstr(m4thx,A,,m4thx,F,,m4thx,K,,f))dnl        fill
  ifelse(m4thtype,,
   `[define(`m4thyd',`dimen_*0.7') eleminit_(`$1',m4thyd); dnl   no type code
     A: last line.start; K: last line.end; T1:A; T2:K
     define(`m4tha',`patsubst(patsubst(patsubst(patsubst(m4thx,UA,Ac),V,B),
      H,ifinstr(m4thf,R,d,u)B),U,c)')dnl
     ifelse(xtract(m4tha,A,F,Q),,`define(`m4tha',m4tha`'A)dnl
      define(`m4thf',m4thf`'ifinstr(m4thx,K,,f))')dnl
     ifelse(xtract(m4tha,B,G,H,N,W),,`define(`m4tha',m4tha`'W)')dnl
     m4gen_d(LRC`'m4tha,m4thf)
     ifinstr(m4thf,E,`Env: circle diam m4thyd with .c at rvec_(rp_len/2,0)')
    `$3']',
    m4thtype,IEC,`bi_trans(`$1',
      ifinstr(m4thf,R,,R),uEdCBUT,xtract(m4thf,E),A:E;K:C;G:T;`$3')',
    `[define(`m4thyd',`dimen_*0.7') eleminit_(`$1',m4thyd)
      A: last line.start; K: last line.end; T1:A; T2:K
      ifelse(m4thtype,SCR,
       `m4gen_d(LCRW`'m4thAc,m4thf)',
      m4thtype,SCS,
       `m4gen_d(LCRWN`'m4thAc,m4thf)',
      m4thtype,SUS,
       `m4gen_d(LFR,m4thf)',
      m4thtype,SBS,
       `m4gen_d(uLYuR,m4thf)',
      m4thtype,B,`ifinstr(m4thf,R,
       `m4gen_d(LdG'xtract(m4thx,G)`dA`'m4thAc`'HuQ`'m4thAc`'R,m4thf)',
       `m4gen_d( LG'xtract(m4thx,G)`uA`'m4thAc`'HdQ`'m4thAc`'R,m4thf)')')
      ifinstr(m4thf,E,`Env: circle diam m4thyd with .c at rvec_(rp_len/2,0)')
     `$3']')')')

                                `scr(linespec, [R][E], label) and similar
                                 Place thyristor as a two-term element with
                                 arg 3 as label of the [] block'
define(`scr',`eleminit_(`$1'); M4_scrS: last line.start; M4_scrE: last line.end
  ifelse(`$3',,,`$3:') thyristor(from M4_scrS to M4_scrE,SCR`'`$2',`$4') \
    with .A at M4_scrS')
define(`scs',`eleminit_(`$1'); M4_scrS: last line.start; M4_scrE: last line.end
  ifelse(`$3',,,`$3:') thyristor(from M4_scrS to M4_scrE,SCS`'`$2'`',`$4') \
    with .A at M4_scrS')
define(`sus',`eleminit_(`$1'); M4_scrS: last line.start; M4_scrE: last line.end
  ifelse(`$3',,,`$3:') thyristor(from M4_scrS to M4_scrE,SUS`'`$2'`',`$4') \
    with .A at M4_scrS')
define(`sbs',`eleminit_(`$1'); M4_scrS: last line.start; M4_scrE: last line.end
  ifelse(`$3',,,`$3:') thyristor(from M4_scrS to M4_scrE,SBS`'`$2'`',`$4') \
    with .A at M4_scrS')

                                `tgate( linespec, [B][R|L] ) Transmission gate
                                 B= box form
                                 L= left orientation'
define(`tgate',`[ eleminit_(`$1') define(`m4tgm',ifinstr(`$2',L,-))
 A: last line.start
 B: last line.end
 C: last line.center
  ifinstr(`$2',B,
   `ebox(from A to B)
 Gb: C+vec_(0,m4tgm`'m4ht/2)
    L1: line from 2 between Gb and C to 4 between Gb and C',
   `m4gen_d(uLAQuR)
    Circle: circle thick max(4pt__,linethick/2) rad m4dh/4 \
      at C+vec_(0,m4tgm`'m4dh/4*4/3)
    L2: line from last circle+vec_(0,m4tgm`'m4dh/4) \
        to C+vec_(0,m4tgm`'m4dh*3/2)
 Gb: Here
    L3: line from C to C-vec_(0,m4tgm`'m4dh) ')
 G: Here
  `$3']')
                                `ptrans( linespec, [R|L] ) Pass transistor
                                 L= left orientation'
define(`ptrans',`[ eleminit_(`$1') define(`m4ptm',ifinstr(`$2',L,-))
  define(`m4pv',`dimen_/6')define(`m4pwd',m4pv*2)dnl
 A: last line.start; Start: A
 B: last line.end; End: B
 C: last line.center
    La1: line to rvec_(rp_len/2-m4pwd/2,0)
    { La2: line to rvec_(m4pwd,m4pv) \
       then to rvec_(m4pwd,neg_(m4pv)) \
       then to Here }
    { La3: line from rvec_(m4pwd,0) \
          to rvec_(0,m4pv) \
       then to rvec_(0,neg_(m4pv)) \
       then to rvec_(m4pwd,0)
    Circle: circle thick max(4pt__,linethick/2) rad m4pv/4 \
      at C+vec_(0,m4ptm`'m4pv*5/6)
    La4: line from last circle+vec_(0,m4ptm`'m4pv/4) \
        to C+vec_(0,m4ptm`'m4pv*2)
 Gb:Here
    La5: line from C-vec_(0,m4ptm`'m4pv/2) \
        to C-vec_(0,m4ptm`'m4pv*3/2)
 G: Here }
    La6: line from rvec_(m4pwd,0) \
        to B
  `$3']')
                                `tline( linespec, wid, len ) Transmission line'
define(`tline',`eleminit_(`$1')
   define(`m4v',`ifelse(`$2',,`dimen_/6',`($2)')')dnl
   define(`m4h',`ifelse(`$3',,`dimen_*2/3',min(rp_len-m4v/2,`$3'))')dnl
   {[box invis ht_ m4v wid_ m4h+m4v/2] at last line.c}
   {line from last line.c+vec_(m4h/2+m4v/4,0) \
        to last line.end}
   {line to 2nd last line.c+vec_(-m4h/2,0); round
    ifdpic(
    `line from rvec_(0,-m4v/2) \
          to rvec_(m4h,-m4v/2)
     spline 0.5523 to rvec_(m4v/4,0) \
       then to rvec_(m4v/4,m4v) \
          to rvec_(0,m4v)
     line to rvec_(-m4h,0)
     spline 0.5523 to rvec_(-m4v/4,0) \
       then to rvec_(-m4v/4,-m4v) \
       then to rvec_(m4v/4,-m4v) \
       then to rvec_(m4v/4,0) \
       then to Here',
    `line from rvec_(m4v/4,-m4v/2) \
          to rvec_(m4h-m4v/4,-m4v/2)
     spline to rvec_(m4v/2,0) \
       then to rvec_(m4v/2,m4v) \
       then to rvec_(0,m4v)
     line to rvec_(-m4h+m4v/2,0)
     spline to rvec_(-m4v/2,0) \
       then to rvec_(-m4v/2,-m4v) \
       then to rvec_(0,-m4v)\
       then to Here \
       then to rvec_(-m4v/2,0) \
       then to rvec_(-m4v/2,-m4v)\
       then to rvec_(0,-m4v)') }
   line to 5th last line.end invis ')

define(`m4_U',`dimen_/10')      `Semiconductor grid size'
define(`m4_Aht',`m4_U*10/6')    `Semiconductor arrowhead ht and wd'
define(`m4_Awd',`m4_U*10/9')

                                `Bipolar transistor bi_tr(linespec, L|R, P, E)'
define(`bi_tr',`bi_trans(`$1',`$2',ifelse(`$3',P,u,d)EBCBU,`$4',`$5')')

                                `Darlington(L|R, chars)
                                 arg2:
                                   E= envelope
                                   P= p-type,
                                   B1= internal base lead,
                                   R1= Q1 bias resistor; E1= ebox,
                                   R2= Q2 bias resistor; E2= ebox,
                                   D= damper diode
                                   Z= zener bias diode
                                 This macro would be somewhat simpler if the
                                 joints had not been mitred (using Along_ and
                                 mitre_)'
define(`Darlington', `[ rpoint_(dimen_/10) define(`m4DR',`ifinstr(`$1',R,-)')
   define(`m4Da',`$2') pushdef(`dimen_',((dimen_)*0.8))dnl Smaller internals
   hp_ang = rp_ang
   Q1: bi_trans(,`$1',ifinstr(m4Da,P,u,d)ECBU)
   E: Q1.E
   Q1B: line from Q1.Bulk.c to Q1.Bulk.c + vec_(0,m4DR`'m4_U)
   Q2: bi_trans(,`$1',ifinstr(m4Da,P,u,d)EBCBU) with .E at Here
   Mitre_(Q1B,Q2.Em0)
   B: Q2.B
   T: Q2.C+(Q2.Bulk.c.x-Q2.B.x,Q2.Bulk.c.y-Q2.B.y)
   QC: intersect_(Q2.C,T,Q1.E,Q1.C)
   C: QC
   L1: line from Along_(Q2.Cm0,hlth) to Q2.C then to QC then to Q1.C \
     then to Along_(Q1.Cm0,hlth)
   define(`m4DE1')sc_draw(`m4Da',E1,`define(`m4DE1',E)define(`m4Da',R1`'m4Da)')
   define(`m4DE2')sc_draw(`m4Da',E2,`define(`m4DE2',E)define(`m4Da',R2`'m4Da)')
   ifinstr(m4Da,E,
    `Env: circle rad 7.75*m4_U at Q1.Bulk.c+vec_(1.5*m4_U,m4DR`'(-0.1*m4_U))
     line from Q1.E to Q1.E+vec_(-2.2*m4_U,0); E: Here
     Mitre_(last line,Q1.Em0)
     line from QC to QC+vec_(2.2*m4_U,0); C: Here
     pushdef(`dotrad_',(dotrad_/2))dnl
     ifelse(ifinstr(m4Da,B1,T,m4Da,R1,T,m4Da,R2,T),T,`dot(at Q2.E)')
     ifelse(ifinstr(m4Da,R2,T,m4Da,Z,T),T,
      `dot(at Q2.Bulk.c+vec_(0,m4DR`'m4_U))')
     ifelse(ifinstr(m4Da,B1,T,m4Da,R1,T),T,`ifinstr(m4Da,R2,
      `dot(at Q2.E+vec_(-m4_U,0))')')
     ifinstr(m4Da,B1,
      `ifinstr(m4Da,R1,`dot(at Q2.E-vec_(3*m4_U,0))')
       B1: Q2.E+vec_(-3*m4_U,m4DR`'5.2*m4_U)
       line from B1 to Q2.E+vec_(-3*m4_U,0); corner')
     ifinstr(m4Da,Z,`dot(at QC+vec_(m4_U*3/2,0))')
     dot(at QC)
     ifinstr(m4Da,D,`dot(at Q1.E)')
     ifinstr(m4Da,R1,`dot(at Q1.E-vec_(m4_U,0))')
     popdef(`dotrad_')',
    `ifinstr(m4Da,B1,`move to Q2.E-vec_(3*m4_U,0); line to rvec_(-m4_U,0)
     B1: Here')') 
   ifelse(ifinstr(m4Da,B1,T,m4Da,R1,T,m4Da,R2,T),T,
    `line from Q2.E to Q2.E-vec_(m4_U,0)
     ifelse(ifinstr(m4Da,B1,T,m4Da,R1,T),T,
      `line to rvec_(-2*m4_U,0)
       ifinstr(m4Da,R1,
        `line to rvec_(-m4_U,0); corner pushdef(`dimen_',((dimen_)*0.6))
         R1: resistor(to Q1.E+vec_(-m4_U/0.6,0),,m4DE1) popdef(`dimen_')
         ifinstr(m4Da,E,,`corner;E: Here; line from Q1.E to E')
         point_(hp_ang)')')')
   ifinstr(m4Da,R2,
    `move to Q2.Bulk.c+vec_(0,m4DR`'m4_U)
     line to rvec_(-4*m4_U,0); corner
     pushdef(`dimen_',((dimen_)*0.6))dnl
     R2: resistor(to Q2.E+vec_(-m4_U/0.6,0),,m4DE2) popdef(`dimen_')
     point_(hp_ang)')
   ifinstr(m4Da,D,
    `DE: Q1.E + vec_(m4_U*3/2,m4DR`'(-m4_U*3/2))
     DS: QC - vec_(m4_U*3/2,m4DR`'m4_U*3/2)
     line from Q1.E to DE
     line from QC to DS
     mitre_(DS,DE,Q1.E)
     mitre_(DE,DS,QC)
     Diode: diode(ifinstr(m4Da,P,`from DS to DE',`from DE to DS'))
     point_(hp_ang)')
   ifinstr(m4Da,Z,
    `ifinstr(m4Da,E,,
      `line from QC to QC+vec_(m4_U*3/2,0); corner; C: Here')
     move to Q2.Bulk.c+vec_(0,m4DR`'m4_U)
     line to rvec_(2*m4_U,0) then to rvec_(4.5*m4_U,m4DR`'(-2*m4_U)) \
       then to rvec_(4.5*m4_U,m4DR`'(-2*m4_U-lthick/4))
     Zener: diode(ifinstr(m4Da,P,`to QC+vec_(m4_U*3/2,0)',
      `from QC+vec_(m4_U*3/2,0) to Here'),Z)
     point_(hp_ang)')
   popdef(`dimen_') `$4' ]')

                                `igbt(linespec, L|R, [L][[d]D])
                                 Arg 3: L = 2nd gate type, D = parallel diode,
                                 dD = dotted connections'
define(`igbt',`bi_trans(`$1',`$2',ifinstr(`$3',L,,GH)CBUdE`$3',,`$4')')

                                `Customizable bi_trans(linespec, L|R, chars, E)
                                 chars
                                   BU=bulk line
                                   B=base line and label
                                   uEn|dEn=emitters E0 to En
                                   uE|dE=emitter line
                                   Cn|uCn|dCn=collectors C0 to Cn (arrow u or d)
                                   C|uC|dC=collector line (arrow u or d)
                                   uT|dT=trigger line
                                   G=gate line and location
                                   H=gate line
                                   L=L-gate line and location
                                   S=Schottky
                                   [d]D=named parallel diode, d=connection dots'
define(`bi_trans',
 `define(`m4R',`ifelse(`$2',R,-)')define(`dna_',`ifelse(`$3',,BCuEBU,`$3')')dnl
  define(`m4n',0)define(`m4dE',)dnl
[ ifelse(`$1',,`tr_xy_init(,m4_U,m4R); E: tr_xy(-3,0); C: tr_xy(3,0)',
   `eleminit_(`$1'); tr_xy_init(last line.c,m4_U,m4R)
    E: last line.start; line from E to tr_xy(-3,0) \
        then to tr_xy(-3,0) + vec_( lthick*0.15,m4R`'lthick/3)
    C: E+vec_(rp_len,0); line from C to tr_xy(3,0) \
        then to tr_xy( 3,0) + vec_(-lthick*0.15,m4R`'lthick/3)')
  Bulk: line sc_draw(`dna_',BU,,invis) from tr_xy(-2,4) \
         to tr_xy(2,4)
  sc_draw(`dna_',B,
   `B: tr_xy(0,6.5); line from B to tr_xy(0,4)')
  for_(1,8,1,
   `sc_draw(`dna_',E`'m4x,`define(`m4n',m4x*1.5) define(`m4dE',m4a)
    m4bi_Em(m4x,m4a,E)
    line from tr_xy(-2,4) \
          to tr_xy(-2-m4n,4)
    Bulk: line invis from tr_xy(-2-m4n,4) \
        to Bulk.end')')
  sc_draw(`dna_',E,
   `define(`m4dE',m4a) m4bi_Em(0,m4a,E)')
  for_(1,8,1,
   `sc_draw(`dna_',C`'m4x,`define(`m4n',m4x*1.5)
    m4bi_Em(m4x,m4a,C)
    line from tr_xy(2,4) \
          to tr_xy(2+m4n,4)
    Bulk: line invis from Bulk.start to tr_xy(2+m4n,4)')')
  sc_draw(`dna_',C,
   `m4bi_Em(0,m4a,C)')
  sc_draw(`dna_',S,
   `Bulk: line invis from Bulk.start+ta_xy(-1,0) \
        to Bulk.end+ta_xy(1,0)
    S1: line from Bulk.end+ta_xy(-1,0) \
        to Bulk.end \
      then to Bulk.end+ta_xy(0,-0.5) \
       then to Bulk.end+ta_xy(-0.5,-0.5)
    S2: line from Bulk.start+ta_xy(1,0) \
        to Bulk.start \
      then to Bulk.start+ta_xy(0,0.5) \
       then to Bulk.start+ta_xy(0.5,0.5)')
  sc_draw(`dna_',T,
   `Tm: line from tr_xy(0,4) \
          to tr_xy(2/3,(4 ifelse(m4a,u,+,-)4/1.8*2/3))
    T: Here')
  sc_draw(`dna_',G,
   `G: tr_xy(0,6.5); line from G to tr_xy(0,4.7)')
  sc_draw(`dna_',H,
   `H1: line from tr_xy(-2,4.7) \
          to tr_xy(2,4.7)')
  sc_draw(`dna_',L,
   `G: tr_xy(-1.5,6.2); line from G to tr_xy(-1.5,4.7) \
       then to tr_xy(1.5,4.7)')
  sc_draw(`dna_',D,
   `D1: line from tr_xy(-5,0) \
          to tr_xy(-5,-4)
    D2: line from tr_xy( 5,0) \
          to tr_xy( 5,-4)
    ifelse(m4a,d,`dot(at tr_xy( 5,0)); dot(at tr_xy(-5,0))')
    Diode: diode(ifelse(m4dE,d,from,to) tr_xy(-5,-4) \
                 ifelse(m4dE,d,to,from) tr_xy( 5,-4))
    ifelse(m4dE,d,,rp_ang = rp_ang + pi_)
    ifelse(`$1',,`E: tr_xy(-5,0); line from E to tr_xy(-3,0);
                  C: tr_xy(5,0);  line from C to tr_xy(3,0)')')
  ifinstr(`$4',E,
   `A1: arc ifelse(`$2',R,c)cw from Bulk.end+ta_xy(-2,2.5) \
      to Bulk.end+ta_xy(-2,-5.5) with .c at Bulk.end+ta_xy(-2,-1.5)
    L1: line to Bulk.start+ta_xy(2,-5.5)
    A2: arc ifelse(`$2',R,c)cw to Bulk.start+ta_xy(2,2.5) \
      with .c at Bulk.start+ta_xy(2,-1.5)
    L2: line to Bulk.end+ta_xy(-2,2.5)')
  `$5'; manhattan ] ')
                                `emitters E0 ... En or collectors C0 ... Cn'
define(`m4bi_Em',
   ``$3'`$1': tr_xy(ifelse(`$3',E,-)(3+(`$1')*1.5),0)
    `$3'm`$1': line from `$3'`$1' to tr_xy(ifelse(`$3',E,-)(1.2+(`$1')*1.5),4)
    ifelse(`$2',,,`arrow m4c_l ht m4_Aht wid m4_Awd ifelse(`$2',d,<-) \
      from 1/4 between `$3'm`$1'.start and `$3'm`$1'.end \
      to 3/4 between `$3'm`$1'.start and `$3'm`$1'.end ')
    ifelse(eval(`$1'>0),1,`m4bi_Em(eval(`$1'-1),`$2',`$3')')')

                                `Unijunction transistor ujt(linespec, R,P,E)
                                   Bulk and terminals B1, B2, E defined
                                   arg 2: drawn to the right of curr direction
                                   arg 3: P-channel, default N
                                   arg 4: envelope'
define(`ujt',
`[ ifelse(`$1',,,`eleminit_($1)')
B1: Here
   ifelse(`$1',,,`line to rvec_(rp_len/2-m4_U*2,0)')
   Bl1: line to rvec_(0,ifelse(`$2',R,-)3.5*m4_U)
Bulk: line from rvec_(-m4_U*0.5,0) \
          to rvec_(m4_U*4.5,0)
   Bl2: line from Bulk.end+vec_(-m4_U/2,0) \
      to Bulk.end+vec_(-m4_U/2,ifelse(`$2',R,,-)3.5*m4_U) ifelse(`$1',,,`\
      then to Bulk.c+vec_(rp_len/2,ifelse(`$2',R,,-)3.5*m4_U)')
B2: Here
E:  Bulk.c+vec_(2*m4_U,ifelse(`$2',R,-)3.5*m4_U)
    E1: line from E to Bulk.center
    {arrow m4c_l from last line.ifelse(`$3',P,`end to 1',`start to 7')/8 \
      between last line.start and last line.end wid m4_Awd ht m4_Aht }
    ifelse(`$4',E,dnl
      `Env: circle rad 4*m4_U with .c at Bulk.c')
   `$5'; manhattan ] ')

                        `FETS:     j_fet(linespec, R, P, E )
                                   e_fet(linespec, R, P, E|S )
                                   d_fet(linespec, R, P, E|S )
                                   c_fet(linespec, R, P )
                                   with terminals S, D, G.
                                   arg 2: G pin drawn to right of curr direction
                                   arg 3: P-channel, default N
                                   arg 4: envelope'
define(`j_fet',`mosfet(`$1',`$2',ifelse(`$3',P,u,d)GSDF,`$4',`$5')')
                                  `Enhancement-mode FET e_fet(linespec,R,P,S,E)'
define(`e_fet',`mosfet(`$1',`$2',
  ifelse(`$4',S,`TFD'ifelse(`$3',P,u,d)S,`LEDSQ'ifelse(`$3',P,d,u)B),
    `$4',`$5')')
                                  `Depletion-mode FET d_fet(linespec,R,P,S,E)'
define(`d_fet',`mosfet(`$1',`$2',
  ifelse(`$4',S,`TFDR'ifelse(`$3',P,u,d)S,`LFDSQ'ifelse(`$3',P,d,u)B),
    `$4',`$5')')
                                `Simplified switching c_fet(linespec,R,P)
                                   arg 3: negated G pin'
define(`c_fet',`mosfet(`$1',`$2',`ZSDF'ifelse(`$3',P,d)T,,`$4')')

 ` The comprehensive mosfet(linespec,R,BDEFGLQRSTXZ,E)
   Every drawn component is controlled by a letter or letter pair in arg 3;
   adding or changing elements is easily done by adding a test for a letter
   or letter sequence:
                               udB: center bulk connection pin; u or d arrow
                                 D: D pin and lead
                                 E: dashed substrate
                                 F: solid-line substrate
                               udG: G pin to substrate at source; u or d arrow
                               udH: G pin to substrate at center; u or d arrow
                                 L: G pin to channel (kept for compatibility
                                    for now; the same as dM below)
                               udM: G pin to channel center or
                                    u: pin at drain end, d: pin at source end
                               udMn: gates G0 to Gn as above
                                Pz: parallel zener diode
                                 Q: connect B pin to S pin
                                 R: thick channel
                               udS: S pin and lead; u or d arrow
                                dT: G pin to center of channel d: not circle
                                 X: XMOSFET terminal
                                 Z: simplified complementary MOS
                                 arg 2: body drawn to right of curr direction
                                 arg 4: envelope'
define(`mosfet',
 `define(`m4R',`ifelse(`$2',R,-)')dnl               right orientation flag
  define(`dna_',`ifelse(`$3',,DSEdMuBQ,`$3')')dnl
  define(`m4s',ifinstr(dna_,Z,2.5,3.5))dnl          size parameter
[ ifelse(`$1',,
   `tr_xy_init(,m4_U,m4R); S: tr_xy(-2,0); D: tr_xy(2,0)',
   `eleminit_(`$1'); tr_xy_init(last line.c,m4_U,m4R)
    S: last line.start; line from S to tr_xy(-2,0) \
         then to tr_xy(-2,0)+vec_(0,m4R`'linethick pt__)
    D: S+vec_(rp_len,0); line from D to tr_xy(2,0) \
         then to tr_xy(2,0)+vec_(0,m4R`'linethick pt__)')
  sc_draw(`dna_',B,
   `B: tr_xy(0,0); Bl: line from B to tr_xy(0,m4s)
    ifelse(m4a,,,`arrow m4c_l ht m4_Aht wid m4_Awd ifelse(m4a,d,<-) \
      from tr_xy(0,m4s/2)-vec_(0,m4R`'m4_Aht/2) \
        to tr_xy(0,m4s/2)+vec_(0,m4R`'m4_Aht/2) ')')
  sc_draw(`dna_',D,
   `Dl: line from tr_xy(2,0) \
          to tr_xy(2,m4s)')
  sc_draw(`dna_',E,
   `Channel: line invis from tr_xy(-2.5,m4s) \
          to tr_xy(2.5,m4s)
    line from tr_xy(-2.5,m4s) \
          to tr_xy(-1,m4s)
    line from tr_xy(-0.5,m4s) \
          to tr_xy(0.5,m4s)
    line from tr_xy(1,m4s) \
          to tr_xy(2.5,m4s)')
  sc_draw(`dna_',F,
   `Channel: line from ifinstr(dna_,Z,
     `tr_xy(-2,m4s) \
          to tr_xy(2,m4s)',
     `tr_xy(-2.5,m4s) \
          to tr_xy(2.5,m4s)')')
  sc_draw(`dna_',G,
   `G: tr_xy(-2,(m4s+3.5))
    ifelse(m4a,,`Gl: line from tr_xy(-2,m4s) \
        to G',
           m4a,d,`Gl: arrow m4c_l from G to tr_xy(-2,m4s) ht m4_Aht wid m4_Awd',
           m4a,u,`Gl: line from tr_xy(-2,m4s) \
        to G; arrow m4c_l ht m4_Aht wid m4_Awd \
             from tr_xy(-2,(m4s+3-m4_Aht/(m4_U))) \
          to tr_xy(-2,(m4s+3))')')
  sc_draw(`dna_',H,
   `G: tr_xy(0,(m4s+4))
    ifelse(m4a,,`Hl: line from tr_xy(0,m4s) \
        to G',
           m4a,d,`Hl: arrow m4c_l from G to tr_xy(0,m4s) ht m4_Aht wid m4_Awd',
           m4a,u,`Hl: line from tr_xy(0,m4s) \
        to G; arrow m4c_l ht m4_Aht wid m4_Awd \
             from tr_xy(0,(m4s+3-m4_Aht/(m4_U))) \
          to tr_xy(0,(m4s+3))')')
  sc_draw(`dna_',L,
   `G: tr_xy(-2,(m4s+3.5))
    Ll: line from tr_xy(2,(m4s+1)) \
          to tr_xy(-2,(m4s+1)) \
          then to G')
  for_(1,4,1,
   `sc_draw(`dna_',M`'m4x,`m4mo_Mm(m4x,m4a,`$4',ifinstr(dna_,Z,2,2.5))')')
  sc_draw(`dna_',M,`ifelse(
    m4a,, `G: tr_xy(0,(m4s+4))
           Glh: line from tr_xy(2,(m4s+1)) \
          to tr_xy(-2,(m4s+1))
           Glv: line from tr_xy(0,(m4s+1)) \
        to G',
    m4a,u,`G: tr_xy(2,(m4s+3.5))
           Gl: line from tr_xy(-2,(m4s+1)) \
          to tr_xy(2,(m4s+1)) \
          then to G',
    m4a,d,`G: tr_xy(-2,(m4s+3.5))
           Gl: line from tr_xy(2,(m4s+1)) \
          to tr_xy(-2,(m4s+1)) \
          then to G')')
  sc_draw(`dna_',Pz,
   `define(`m4q',m4a)dnl
    Diode: diode(ifelse(m4q,d,to,from) tr_xy(-2,-2) \
                 ifelse(m4q,d,from,to) tr_xy( 2,-2),Z)
    ifelse(m4q,d,rp_ang = rp_ang + pi_)
    line from tr_xy(-2,0) \
          to tr_xy(-2,-2) \
      then to tr_xy(2,-2) \
      then to tr_xy(2,0)')
  sc_draw(`dna_',Q,
   `Ql: line from tr_xy(0,0)+vec_(0,m4R`'linethick pt__) \
          to tr_xy(0,0) \
      then to tr_xy(-2,0) \
      then to tr_xy(-2,0)+vec_(0,m4R`'linethick pt__)')
  sc_draw(`dna_',R,
   `Rl: line thick 2*linethick from tr_xy(-2,m4s)\
         -vec_(0,m4R`'linethick*3/2 pt__) \
          to tr_xy(2,m4s)-vec_(0,m4R`'linethick*3/2 pt__) ')
  sc_draw(`dna_',S,
   `Sl: line from tr_xy(-2,0) \
          to tr_xy(-2,m4s)
    ifelse(m4a,,,`arrow m4c_l ht m4_Aht wid m4_Awd ifelse(m4a,d,<-) \
      from tr_xy(-2,m4s/2)-vec_(0,m4R`'m4_Aht/2) \
        to tr_xy(-2,m4s/2)+vec_(0,m4R`'m4_Aht/2) ')')
  sc_draw(`dna_',T,
   `Tl: line from tr_xy(-2,(m4s+1)) \
          to tr_xy(2,(m4s+1))
    ifelse(m4a,d,`Nt: circle rad m4_U*2/3 with .c at tr_xy(0,(m4s+1+2/3))')
    Gl: line from tr_xy(0,`(m4s+1'`ifelse(m4a,d,+4/3))') \
           to tr_xy(0,ifelse(`$4',E,(m4s+4),(m4s+4))); G: Here')
  sc_draw(`dna_',X,dnl          From Matteo Agostinelli
   `B: tr_xy(0,0); Xv: line from B to tr_xy(0,m4s-1)
       Xh: line from tr_xy(-1.5,m4s-1) \
          to tr_xy(1.5,m4s-1)')
  ifelse(`$4',E,`Env: circle rad 4*m4_U with .c at tr_xy(0,m4s)')
  `$5'; manhattan ] ')
define(`m4mo_Mm',dnl                 (m4n,m4a,[E])
 `define(`m4mo_d',`eval((`$1')*2+1)')dnl
  for_(0,`$1',1,
   `define(`m4moc',`ifelse(`$2',u,
     ` (`$4')-`$4'*4*m4x/m4mo_d',`-`$4'+`$4'*4*m4x/m4mo_d')')dnl
    ifinstr(`$3',E,
     `M4moM: move from tr_xy(m4moc,m4s) to tr_xy(m4moc,m4s+1)
      G`'m4x: LCintersect(M4moM,tr_xy(0,m4s),4*m4_U,R)',
     `G`'m4x: tr_xy(m4moc,m4s+4)')
    Gm`'m4x: line from G`'m4x to tr_xy(m4moc,m4s+1) \
      then to tr_xy(m4moc`'ifelse(`$2',u,-,+)2*`$4'/m4mo_d,m4s+1) ') ')

                               `Macro-internal coordinates adjusted for L|R'
define(`ta_xy',`vec_(vscal_(m4_xyU,`$1',ifelse(`$2',0,0,m4_xyS`($2)')))')
                               `Relative adjusted macro-internal coordinates'
define(`tr_xy',`M4_xyO+vec_(vscal_(m4_xyU,`$1',ifelse(`$2',0,0,m4_xyS`($2)')))')
                               `Initialize tr_xy_init(origin,unit,-)'
define(`tr_xy_init',`M4_xyO: ifelse(`$1',,Here,`$1')
define(`m4_xyU',`$2')dnl
define(`m4_xyS',`$3')')

                               `Extract substring plus preceding char if u or d'
define(`m4_dna',`define(`m4I_',index($1,`$2'))dnl
ifelse(m4I_,-1,`define(`m4t',0)',`define(`m4t',eval(m4I_+len($2)))dnl
define(`m4a',ifelse(substr($1,decr(m4I_),1),u,`define(`m4I_',decr(m4I_))'u,
                    substr($1,decr(m4I_),1),d,`define(`m4I_',decr(m4I_))'d))dnl
define(`$1',substr($1,0,m4I_)`'substr($1,m4t))')')dnl

                               `Conditional subcomponent draw
                                sc_draw(dna string, chars, iftrue, iffalse)'
define(`sc_draw',`m4_dna(`$1',`$2')ifelse(m4I_,-1,`$4',`$3')')

                               `Element labels to the left, right, centre of
                                the current direction.  Labels are spaced and
                                treated as math, but copied literally if double
                                quoted or defined by sprintf'
                               `The hash (pound sign) is used in svg text so
                                we temporarily turn off comments for svg' 
define(`rlabel',`ifsvg(`changecom(,)')dnl
m4label(`$1',`$2',`$3',.s_,below_,`$4')`'ifsvg(`changecom(`#',)')')
define(`llabel',`ifsvg(`changecom(,)')dnl
m4label(`$1',`$2',`$3',.n_,above_,`$4')`'ifsvg(`changecom(`#',)')')
define(`clabel',`ifsvg(`changecom(,)')dnl
m4label(`$1',`$2',`$3',,,`$4')`'ifsvg(`changecom(`#',)')')
                   labels at centre and both ends of an element `dimen_' long
define(`m4label',`dnl
 ifelse(`$1',,,
  `{m4lstring(`$1',"sp_`'iflatex(`$ `$1'$',`$1')`'sp_") \
     at last [].w_ $5 rjust_ $6};')dnl
 ifelse(`$2',,,
  `{m4lstring(`$2',"sp_`'iflatex(`$ `$2'$',`$2')`'sp_") \
     at last []$4 $5 $6};')dnl
 ifelse(`$3',,,
  `{m4lstring(`$3',"sp_`'iflatex(`$ `$3'$',`$3')`'sp_") \
     at last [].e_ $5 ljust_ $6};')dnl
 ')
                               `Labels for oblique or aligned elements
                                dlabel(long,lateral,label,label,label,chars)
                                long, lateral: dispacement with respect to
                                  drawing direction
                                chars:
                                  X displacement is from the centre of the last
                                    line rather than the centre of the last []
                                  L,R,A,B align labels ljust, rjust, above,
                                    or below (absolute) respectively'
define(`dlabel',`ifsvg(`changecom(,)')dnl
 ifelse(`$3',,,
  `{m4lstring(`$3',"iflatex(`$ `$3'$',` $3')") \
     at last ifinstr(`$6',X,line,[]).c+vec_(-(`$1'),`$2') \
     ifinstr(`$6',L,ljust,`$6',R,rjust) dnl
     ifinstr(`$6',A,above,`$6',B,below) };') dnl
 ifelse(`$4',,,
  `{m4lstring(`$4',"iflatex(`$ `$4'$',` $4')") \
     at last ifinstr(`$6',X,line,[]).c+vec_(0,`$2') \
     ifinstr(`$6',L,ljust,`$6',R,rjust) dnl
     ifinstr(`$6',A,above,`$6',B,below) };') dnl
 ifelse(`$5',,,
  `{m4lstring(`$5',"iflatex(`$ `$5'$',` $5')") \
     at last ifinstr(`$6',X,line,[]).c+vec_(`$1',`$2') \
     ifinstr(`$6',L,ljust,`$6',R,rjust) dnl
     ifinstr(`$6',A,above,`$6',B,below) };') ifsvg(`changecom(`#',)')')

                               `eleminit_( linespec, default length )
                                compute element direction and length.
				                Eleminit_ defines the position, length,
				                and angle of two-terminal elements.  It calls
                                rpoint_ with its linespec or circuit-element
                                default. The rpoint_ macro draws the invisible
                                line determined by its argument, calculates the
                                length and angle, and gives the angle to the
                                point_ macro to set the rotation parameters used
                                by vec_ and rvec_.'
define(`eleminit_',
 `rpoint_(ifelse(`$1',,`to rvec_(ifelse(`$2',,`elen_',`$2'),0)',`$1'))')

                              `parallel_(`elementspec', `elementspec', ...
                               Parallel combination of two-terminal elements
                               in a [ ] block. Each elementspec is quoted and
                               of the form
                               [Sep=val;][Label:] element; [attributes]
                               where an attribute is of the form
                                [llabel(...);]|[rlabel(...);][b_current(...);]
                               Sep=val; in the first branch sets the default
                               separation of all branches to val; in a later
                               element Sep=val; applies only to that branch.
                               An element may have normal arguments but should
                               not change the drawing direction.
                               An argument may also be series_(args) or
                               parallel_(args) without attributes or quotes.
                               example:
                               define(`elen_',dimen_) setdir_(Down)
                               parallel_(
                                 `resistor;llabel(,R);inductor(,W);llabel(,L)',
                                 `capacitor;rlabel(,C)')
'
define(`parallel_',
`[ ifdef(`m4rp_ang',rp_ang = m4rp_ang;) pwid = 0
 stackargs_(`m4parR',$@) stackexec_(`m4parR',`m4parS')dnl
 define(`m4br',0) define(`m4parsep',`m4sepdefault')dnl
 stackdo_(`m4parS',
  `define(`m4pel',m4parS)
   setkey_(m4pel,Sep,m4parsep)dnl
   ifelse(m4br,0,`define(`m4parsep',m4Sep)')dnl
   ifinstr(m4pel,Sep=,`define(`m4pel',substr(m4pel,eval(index(m4pel,;)+1)))')
   E`'eval(m4br+1): [
     Start: Here
     m4pel
     End: Here
     C: 0.5 between Start and End
     ] ifelse(m4br,0,,`with .C at C`'m4br-vec_(0,m4Sep)')
   define(`m4br',incr(m4br))dnl
   Start`'m4br: E`'m4br.Start; End`'m4br: E`'m4br.End; C`'m4br: E`'m4br.C
   pwid = max(pwid,distance(Start`'m4br,End`'m4br))
   ')
 U: Vdiff_(End1,Start1)
 d = vlength(U.x,U.y); if d==0 then { d=1 } else { d = 1/d }
 Unit: Vsprod_(U,d)
 line from C1-(Vsprod_(Unit,pwid/2)) to C`'m4br-(Vsprod_(Unit,pwid/2)) \
   chop -lthick/2
 Start: last line.c
 line from C1+Vsprod_(Unit,pwid/2) to C`'m4br+Vsprod_(Unit,pwid/2) \
   chop -lthick/2
 End: last line.c; C: 0.5 between Start and End
 for_(1,m4br,1,`
   line from Start`'m4x to C`'m4x-Vsprod_(Unit,pwid/2)
   line from   End`'m4x to C`'m4x+Vsprod_(Unit,pwid/2)')
 ] with .Start at Here; move to last [].End
')

                               `par_( element, element, separation )
                                Parallel combination of two branches that have
                                the same direction and length. The
                                branch arguments must be quoted, e.g.
                                par_(`resistor',`capacitor',dimen_)'
` ***WARNING: this macro is considered obsolete'
define(`par_',`[Start: Here; r = ifelse(`$3',,`dimen_',`$3')
   { move to Start + vec_(0,r/2);  $1 }
   line from Start + vec_(0,r/2) \
        to Start + vec_(0,-r/2) ; $2
   line to rvec_(0,r)
   End: last line.c; `$4'] with .Start at Here
   move to last [].End')

                               `gpar_( element, element, separation )
                                Parallel combination of two branches that have
                                the same direction, e.g.:
                                down_; gpar_(
                                  resistor;llabel(,R_1);resistor;llabel(,R_2),
                                  capacitor;rlabel(,C))
                                This macro trades simplicity for generality
                                and robustness to gpic'
` ***WARNING: this macro is considered obsolete'
define(`gpar_',
 `[ M4_B1: Here; `$1'; M4_E1: Here
    M4_C: 0.5 between M4_B1 and M4_E1; eleminit_(from M4_B1 to M4_E1)
    E2:[ M4_B: Here; `$2';  M4_E: Here; `$4'] \
      with .c at M4_C + (rect_(ifelse(`$3',,`dimen_',`$3'),rp_ang-pi_/2))
    M4_B2: E2.M4_B; M4_E2: E2.M4_E
    s = distance(M4_B2,M4_E2)
    if rp_len*s == 0 then { r = 1 } else { r = (1+max(rp_len/s, s/rp_len))/2 }
    if rp_len < s then { Tmp:M4_B2; M4_B2:M4_B1; M4_B1:Tmp
                         Tmp:M4_E2; M4_E2:M4_E1; M4_E1:Tmp }
    line from M4_B2 to r between M4_E2 and M4_B2
  Start: 0.5 between Here and M4_B1; line to M4_B1
    line from M4_E2 to r between M4_B2 and M4_E2
  End: 0.5 between Here and M4_E1
  C: 0.5 between Start and End; line to M4_E1 ] with .Start at Here
    move to last [].End ')

define(`m4sepdefault',`dimen_') `Default separation in the parallel_ macro'
define(`m4lendefault',`dimen_') `Default length in the series_ macro'

                              `series_(elementspec, elementspec, ... )
                               Series combination in a [] block of elements
                               with shortened default length
                               An elementspec is of the form
                                [Label:] element; [attributes]
                               where an attribute is of the form
                                [llabel(...);]|[rlabel(...);][b_current(...);]
                               Internal points Start, End, and C are defined
                               automatically.'
define(`series_',
`[ pushdef(`elen_',m4lendefault)dnl
 stackargs_(`m4serR',$@) stackexec_(`m4serR',`m4serS')dnl
 ifdef(`m4rp_ang',rp_ang = m4rp_ang;) Start: Here
 stackdo_(`m4serS',`m4serS
') End: Here;
 C: 0.5 between Start and End
 popdef(`elen_')] with .Start at Here; move to last [].End
')


                                `reversed(`macro name in quotes', macro args)
                                 reverse polarity of two-terminal element'
define(`reversed',`eleminit_(`$2')
  $1(from last line.end to last line.start,shift(shift($@)))
  rp_ht = -rp_ht; rp_wid = -rp_wid; rp_ang = rp_ang - pi_
  line invis to last line.start ')

                                `resized(factor,`macro name in quotes',args)
                                 multiply element body size by factor'
define(`resized',`define(`m4resiztmp',dimen_)define(`dimen_',(dimen_)*(`$1'))dnl
  $2(shift(shift($@))) define(`dimen_',m4resiztmp)')

                                `variable(`element', type, angle, length)
                                 overlaid arrow or line on two-terminal element
                                 to show variablility: type = [A|P|L|[u]N][C|S]
                                 A=arrow, P=preset, L=linear, N=nonlinear,
                                 C=continuous, S=setpwise'
define(`variable',`$1
 {[ define(`dna_',`ifelse($2,,A,$2)') ang = ifelse(`$3',,45,`$3')
 M4_T: Here+(Rect_(ifelse(`$4',,`dimen_*0.8',`$4'),ang))
   sc_draw(`dna_',P,`Line: line to M4_T
     [line to (Rect_(dimen_/6,ang-90))] at Line.end')
   sc_draw(`dna_',L,`Line: line to M4_T')
   sc_draw(`dna_',N,`Line: line to M4_T
     ifelse(m4a,u,`line up dimen_/6 from Line.end',
                  `line left dimen_/6 from Line.start')')
   sc_draw(`dna_',A,`Line: arrow to M4_T')
   sc_draw(`dna_',C,`move to Line.end+(dimen_*0.10,-dimen_*0.06)
     line to Here+(Rect_(dimen_/6,ang))')
   sc_draw(`dna_',S,`move to Line.end+(dimen_*0.10,-dimen_*0.12)
     line up dimen_*0.06 then right dimen_*0.12 then up dimen_*0.06')
   `$5'] with .Line.c at last [].c } ')

                                `Line hopping over named lines,
                                 diverting left or right:
                                crossover(linespec,L|R,line_name,line_name,...)'
define(`hoprad_',`dimen_/12')
define(`crossover',`eleminit_(`$1')dnl
  M4_Tmp: last line.end
  m4_xover_(shift($@))dnl
  line to M4_Tmp')
define(`m4_xover_',
 `define(`m4_lt2',`ifelse(ifpstricks(T)`'ifmpost(T)`'ifpgf(T)`'ifsvg(T),T,
   `hlth',0)')dnl
  ifelse(`$2',,,
   `line to intersect_(last line.start,M4_Tmp,`$2'.start,`$2'.end)\
      chop 0 chop hoprad_-m4_lt2
    ifelse(`m4_lt2',0,,`move to rvec_(-m4_lt2,0)')
    arc ifelse(`$1',R,c)cw to rvec_(2*hoprad_,0) with .c at rvec_(hoprad_,0)
    ifelse(`m4_lt2',0,,`move to rvec_(-m4_lt2,0)')
    m4_xover_(`$1',shift(shift($@)))')')

                                `NPDT(npoles,chars) Double throw switch
                                 chars:
                                   R = right orientation'
define(`NPDT',`[define(`m4np',`ifelse(`$1',,1,`$1')')dnl
define(`m4xR',ifinstr(`$2',R,R))define(`m4SR',ifelse(m4xR,R,-))dnl
  for_(1,m4np,1,
   `{ L`'ifelse(eval(m4np>1),1,m4x): dot(at rvec_(-dimen_/3,0),,1) }
    { X: Here
      T`'ifelse(eval(m4np>1),1,m4x): circle invis rad dotrad_ at X
      lswitch(from X to X+vec_(dimen_/3,0),m4xR,D)
      R`'ifelse(eval(m4np>1),1,m4x): circle invis rad dotrad_ at Here }
    ifelse(eval(m4x<m4np),1,`move to rvec_(0,m4SR`'dimen_/2)') ')
  ifelse(eval(m4np>1),1,`move to vec_(dimen_/6,m4SR`'dimen_/10)
    DL: line dashed to rvec_(0,m4SR`'(m4np-3/4)*dimen_/2)') 
`$3']')

                                `relay(npoles,chars,[L|R])
                                 arg1: Number of poles (max 10)
                                 chars:
                                   O = normally open
                                   C = normally closed
                                   P = three position
                                   neither = double-throw (default)
                                   L = drawn left (default)
                                   R = drawn right
                                   T = thermal
                                 arg3: deprecated, kept for compatibility
                                   L = drawn left (default)
                                   R = drawn right '
define(`relay',`[ define(`m4n',`ifinstr(`$2',R,-,`$3',R,-,0+)')
V1: Here
  L1: line to rvec_(dimen_/5,0)
  Box: lbox(dimen_/5,dimen_/2)
  ifinstr(`$2',T,`{move to rvec_(-dimen_/10,0)
   line from rvec_(-dimen_/20,dimen_/6) \
   to rvec_(-dimen_/20,dimen_/20) \
      then to rvec_(dimen_/20,dimen_/20) \
   then to rvec_(dimen_/20,-dimen_/20) \
      then to rvec_(-dimen_/20,-dimen_/20) \
   then to rvec_(-dimen_/20,-dimen_/6)}')
  L2: line to rvec_(ifinstr(`$2',P,,2*)dimen_/5,0)
V2: Here
  move to V2+vec_(0,m4n (dimen_/4+dimen_/5))
  m4_contacts(1,ifelse(`$1',,1,`$1'),
    ifinstr(`$2',O,O,`$2',C,C)`'ifinstr(`$2',P,P)`'ifinstr(`$2',I,I),
    ifinstr(`$3',R,R,`$2',R,R))
  ifelse(`$1',,,`ifelse(eval(`$1'>1),1,`DL: line dashed \
    from P1+vec_(dimen_*0.261,-(m4n dimen_/10)) \
    to P`'ifelse(`$1',,1,`$1')+vec_(dimen_*0.261,m4n dimen_/10)')')
  `$4'] ')
define(`m4_contacts',`contact(`$3',`$4') with .O at Here
  define(`m4v',`ifelse(`$1',,1,`$1')')dnl
  P`$1': circle invis rad dotrad_ at last [].P
  ifelse(`$3',O,,C`$1': last [].C)
  ifelse(`$3',C,,O`$1': last [].O)
  ifelse(m4v,`$2',,
   `move to last[].C+(0,m4n dimen_/5)
    ifelse(eval(m4v<11),1,`m4_contacts(incr(m4v),`$2',`$3',`$4')')')')

                                `reed(linespec,wid,ht,box attributes,[R][C])
                                 Enclosed two-terminal reed contact;
                                 R=right orientation;
                                 C=closed;
                                 e.g. reed(,,dimen_/5,shaded "lightgreen"'
define(`reed',`eleminit_(`$1')
   define(`m4wd',ifelse(`$2',,`dimen_*0.8',`($2)'))dnl
   define(`m4ht',ifelse(`$3',,`dimen_*0.3',`($3)'))dnl
   define(`m4ng',`ifinstr(`$5',R,-)')dnl
   {line to rvec_(max(0,rp_len/2-m4wd/2),0)
    {rotbox(m4wd,m4ht,$4,r=m4ht/2)}
    {line to rvec_(m4wd*0.2,0) then to \
      rvec_(m4wd*0.6,m4ng`'ifinstr(`$5',C,lthick,m4ht/3))} 
    line from rvec_(m4wd*0.5,0) to rvec_(m4wd,0)
    line to rvec_(max(0,rp_len/2-m4wd/2),0)}
  {[box invis ht_ m4ht wid_ m4wd] at rvec_(rp_len/2,0)}
   line to rvec_(rp_len,0) invis ')

                                `contact(chars [,R]) Relay contact switch
                                 Arg 2 deprecated, kept for compatibility
                                 chars:
                                  P|O|C= three position, normally open,
                                   normally closed
                                  R= right orientation (default left)
                                  I= open circles for contacts'
define(`contact',`[define(`m4n',`ifelse(ifinstr(`$1',R,R,`$2',R,R),R,-,0+)')dnl
  define(`m4dr',`dotrad_')dnl
  P: dot(,m4dr,1); line to rvec_(dimen_/2,0) chop m4dr chop 0
  T: P+vec_(dimen_/2-dimen_/12,0)
  O: circle invis rad dotrad_ at T+vec_(dimen_/5,-(m4n dotrad_))
  C: circle invis rad dotrad_ at T+vec_(dimen_/5,m4n dotrad_)
  ifinstr(`$1',O,,`move to T ifinstr(`$1',P,`+vec_(0,m4n`'dimen_/8)')
   ifinstr(`$1',I,
   `C: dot(at rvec_(0,m4n`'(m4dr`'ifinstr(`$1',P,*2)+lthick/2)),m4dr,1)',
   `arrow m4c_l <- ht dimen_/6 wid dimen_/6 \
     to rvec_(0,m4n`'dimen_/4) \
     then to rvec_(dimen_/5,m4n`'dimen_/4)
  C: Here')')
  ifinstr(`$1',C,,`move to T+vec_(0,-(m4n`'dimen_/8))
   ifinstr(`$1',I,
   `O: dot(at rvec_(0,m4n`'(-m4dr*2)),m4dr,1)',
   `arrow m4c_l <- ht dimen_/6 wid dimen_/6 \
     to rvec_(0,-(m4n`'dimen_/4)) \
     then to rvec_(dimen_/5,-(m4n`'dimen_/4))
  O: Here')'); `$3'] ')


                     `ccoax(at location,M|F,diameter)'
define(`ccoax',`[define(`m4cd',ifelse(`$3',,`dimen_*0.4',`$3'))dnl
  S: circle diam m4cd
  C: circle diam m4cd/3 fill_(ifinstr(`$2',F,1,0)) at S
  `$4'] with .c ifelse(`$1',,`at Here',`$1')')

                          `tconn( linespec, >|>>|<|<<|O[F], wid)
                           terminal connector
                                 O=node (circle); OF=filled circle
                                 > (default) or >> =output
                                 < or << =input
                                 arg3 is arrowhead width or circle diam'
define(`tconn',
 `define(`m4ph',`ifelse(`$3',,`dimen_/6',`($3)/2')')dnl
  define(`m4ps',`dimen_/8') define(`m4cd',`ifelse(`$3',,`dimen_/5',`$3')')dnl
  eleminit_(`$1',dimen_*3/4)
  M4Ss: last line.start; M4Se: last line.end
  ifelse(ifinstr(`$2',0,O,`$2'),O,
   `{circle diam m4cd ifinstr(`$2',OF,`fill_(0)') ifinstr(`$2',0F,`fill_(0)') \
       at (m4cd)/2/distance(M4Ss,M4Se) between M4Se and M4Ss}
    {line to last line.end chop 0 chop m4cd}',
 `$2',<<,
   `{line to last line.end chop 0 chop m4ps+m4ph
     {line from rvec_(m4ph,m4ph) to Here then to rvec_(m4ph,-m4ph)}
     move to rvec_(m4ps,0)
     line from rvec_(m4ph,m4ph) to Here then to rvec_(m4ph,-m4ph)}',
 `$2',<,
   `{line to last line.end chop 0 chop m4ph
     line from rvec_(m4ph,m4ph) to Here then to rvec_(m4ph,-m4ph)}',
 `$2',>>,
   `{line to last line.end chop 0 chop m4ps
     {line from rvec_(-m4ph,m4ph) to Here then to rvec_(-m4ph,-m4ph)}
     move to rvec_(m4ps,0)
     line from rvec_(-m4ph,m4ph) to Here then to rvec_(-m4ph,-m4ph)}',
 `{line to last line.end
   line from rvec_(-m4ph,m4ph) to Here then to rvec_(-m4ph,-m4ph)}')
  line invis to M4Se')

                          `tbox( text,wid,ht,<|>|<>,type )
                           Pointed terminal box.
                           text is placed at centre of rectangle in math mode
                           unless it starts with a double quote or sprintf
                           arg4= > point on right end (default)
                                 < point on left end; <> both ends
                           Defaults: wid dimen_*2/3 ht dimen_/3 
                           type= eg dotted outlined "red"
                           eg tbox(`$V_2$', 30pt__, 15pt__,,fill_(0.9) )' 
define(`tbox',`[ define(`m4td',`ifelse(`$4',,>,`$4')')
  pushdef(`m4tw2',`ifelse(`$2',,(dimen_*0.4),`(($2)/2)')')dnl
  pushdef(`m4th2',`ifelse(`$3',,(dimen_/6),`(($3)/2)')')dnl
  N: vec_(0,m4th2)
  NE: N+vec_(m4tw2 ifinstr(m4td,>,-m4th2),0)
  E: vec_(m4tw2,0)
  SE: NE+vec_(0,-m4th2*2)
  NW: N-vec_(m4tw2 ifinstr(m4td,<,-m4th2),0)
  W: vec_(-m4tw2,0)
  SW: NW+vec_(0,-m4th2*2)
  C: 0.5 between SW and NE
  line from N to NE ifinstr(m4td,>,then to E) then to SE \
    then to SW ifinstr(m4td,<,then to W) then to NW then to N `$5'
  move to C
  ifelse(`$1',,,`m4lstring(`$1',`"iflatex(`$ `$1'$',` $1')"')')
  `$6' popdef(`m4th2') popdef(`m4tw2') ]')

                          `pconnex(R|L|U|D|degrees,chars)
                           arg1: drawing direction
                           chars:
                            R=right orientation
                            M|F= male, female
                            A[B]|AC =115V 3-prong, B=box (default), C=circle
                            P= PC connector
                            D= 2-pin connector
                            G[B]|GC= 3-pin, B=default, C=circle
                            J= 110V 2-pin '
define(`pconnex',
 `[ define(`m4sgn',ifinstr(`$2',F,,-))define(`m4R_',ifinstr(`$2',R,-))dnl
  setdir_(`$1')
  define(`m4na_',`ifelse(`$2',,A,`$2')')dnl
  ifinstr(m4na_,A,`
    Base: ifinstr(m4na_,AC,`circle diam dimen_',`[lbox(dimen_,dimen_) ]')
    N: m4pconpin(dimen_/12,dimen_*0.3,m4na_) \
          at Base+vec_(m4sgn`'(-dimen_*0.2),m4R_`'dimen_*0.15)
    H: m4pconpin(dimen_/12,dimen_*0.25,m4na_) \
          at Base+vec_(m4sgn`'(dimen_*0.2),m4R_`'dimen_*0.15)
    gd = dimen_/12
    G: [ifelse(ifgpic(T)`'ifinstr(m4na_,F,,T),TT,
        `circle fill_(m4fill) rad gd at vec_(0,m4R_`'gd/2)
         box fill_(m4fill) wid 2*gd ht gd at vec_(0,0)',
        `arc ifinstr(m4na_,R,,c)cw rad gd from vec_(gd,m4R_`'gd/2) \
           to vec_(-gd,m4R_`'gd/2) with .c \
           at vec_(0,m4R_`'gd/2) ifinstr(m4na_,F,,
            `ifdef(`r_',`shaded rgbstring(r_,g_,b_)',`fill_(m4fill)')')
         line from vec_(-gd,m4R_`'gd/2) \
            to vec_(-gd,m4R_`'(-gd/2)) \
            then to vec_(gd,m4R_`'(-gd/2)) \
            then to vec_(gd,m4R_`'gd/2) ifinstr(m4na_,F,,
             `ifdef(`r_',`shaded rgbstring(r_,g_,b_)',`fill_(m4fill)')')')
         ] at Base+vec_(0,m4R_`'(-dimen_*0.25))',
  m4na_,P,
   `wd = dimen_; hd = wd*3/4
    Base: [line to vec_(-wd/2,0) \
      then to vec_(-wd/2,-hd*2/3) \
      then to vec_(-wd/2+hd/3,-hd) \
      then to vec_(wd/2-hd/3,-hd) \
      then to vec_(wd/2,-hd*2/3) \
      then to vec_(wd/2,0) \
      then to Here]
    N: m4pconpin(dimen_/12,dimen_*0.25,m4na_) \
          at Base+vec_(m4sgn`'(-dimen_*0.2),m4R_`'dimen_*0.15)
    H: m4pconpin(dimen_/12,dimen_*0.25,m4na_) \
          at Base+vec_(m4sgn`'(dimen_*0.2),m4R_`'dimen_*0.15)
    G: m4pconpin(dimen_/12,dimen_*0.20,m4na_) \
          at Base+vec_(0,m4R_`'(-dimen_*0.15))',
  m4na_,D,
   `wd = dimen_*1.2; hd = wd/2
    Base: [line to vec_(wd-hd,0)
      arc rad hd/2 ccw to rvec_(0,hd) with .c at rvec_(0,hd/2)
      line to rvec_(hd-wd,0)
      arc rad hd/2 ccw to rvec_(0,-hd) with .c at rvec_(0,-hd/2) ]
    H: m4pcrpin(dimen_/6,m4na_) at Base.c+vec_( (wd-hd)/2,0)
    N: m4pcrpin(dimen_/6,m4na_) at Base.c+vec_(-(wd-hd)/2,0)',
  m4na_,G,
   `wd = dimen_*1.3; hd = dimen_*1.2
    Base: ifinstr(m4na_,GC,`circle diam wd',
     `[line to vec_(wd/2,0) \
      then to vec_(wd/2,-hd*0.3) \
       then to vec_(hd*0.15,-hd) \
      then to vec_(-hd*0.15,-hd)\
       then to vec_(-wd/2,-hd*0.3) \
      then to vec_(-wd/2,0) \
      then to Here ]')
    H: m4pconpin(dimen_*0.25,dimen_/8,m4na_) \
         at Base.c+vec_(-dimen_/3,dimen_*0.3)
    N: m4pconpin(dimen_*0.25,dimen_/8,m4na_) \
         at Base.c+vec_( dimen_/3,dimen_*0.3)
    G: m4pconpin(dimen_/8,dimen_*0.25,m4na_) \
         at Base.c+vec_(0,-dimen_/3)',
  m4na_,J,
   `wd = dimen_; hd = wd/2
    Base: [line to vec_(wd/2,0) \
      then to vec_(wd/2,hd) \
      then to vec_(-wd/2,hd) \
      then to vec_(-wd/2,0) \
      then to Here ]
    H: m4pconpin(dimen_/12,dimen_*0.25,m4na_) at Base.c+vec_( wd/4,0)
    N: m4pconpin(dimen_/12,dimen_*0.25,m4na_) at Base.c+vec_(-wd/4,0)
    ')
  `$3' ; resetdir_ ]')
define(`m4pconpin',`[ifinstr(`$3',F,`lbox(`$1',`$2')',
 `m4fshade(m4fill,lbox(`$1',`$2'))')]')
define(`m4pcrpin',`[ifinstr(`$2',F,`circle diam `$1'',
 `m4fshade(m4fill,circle diam `$1')')]')

                          `Header(1|2,rows,wid,ht,type)
                            arg1: number of columns
                            arg2: pins per column
                            arg3,4: custom sizes
                            arg5: eg fill_(0.9)'
define(`Header',
`[define(`m4Hm',`ifelse(`$2',,2,`$2')')define(`m4Hn',`ifelse(`$1',,1,`$1')')dnl
  define(`m4Hw',`ifelse(`$3',,`m4Hn*L_unit*3',`($3)')')dnl
  define(`m4Hh',`ifelse(`$4',,`m4Hm*L_unit*3',`($4)')')dnl
  Block: rotbox(m4Hw,m4Hh,`$5')
  define(`m4Hct',1)dnl
  for_(1,m4Hm,1,
   `HeaderPin(Block.NW+vec_(L_unit*3/2,-(m4x-1/2)*m4Hh/m4Hm),
     eval(m4Hct-1), P`'m4Hct,w) define(`m4Hct',incr(m4Hct))
    ifelse(m4Hn,2,`HeaderPin(Block.NE+vec_(-L_unit*3/2,-(m4x-1/2)*m4Hh/m4Hm),
        1, P`'m4Hct,e) define(`m4Hct',incr(m4Hct))') ')
  `$6' ]')
                          `HeaderPin(location,type,Picname,
                            n|e|s|w,length)'
define(`HeaderPin',`define(`m4Hpl',`ifelse(`$5',,`lg_plen*L_unit',`$5')')dnl
  move to `$1'
  line to ifelse(`$4',n,`rvec_(0,m4Hpl)',
   `$4',e,`rvec_(m4Hpl,0)',`$4',s,`rvec_(0,-m4Hpl)',`rvec_(-m4Hpl,0)')
  ifelse(`$3',,,`$3': Here)
  ifelse(`$3',,,Pin`$3':) ifelse(`$2',0,
   `rotbox(L_unit,L_unit,fill_(1))',
   `circle diam L_unit fill_(1)') at last line.start ')

                    `nport(box specs; other commands,
                       nw,nn,ne,ns,
                       space ratio,pin lgth,style,other commands)
                     Default is a standard-box twoport.  Args 2 to 5 are
                     the number of ports to be drawn on w, n, e, s sides.
                     The port pins are named by side, number, and by a or b pin,
                     e.g. W1a, W1b, W2a, ... .  Arg 6 specifies the ratio of
                     port width to interport space (default 2), and arg 7 is
                     the pin length.  Set arg 8 to N to omit the dots on
                     the port pins. Arguments 1 and 9 allow customizations'
define(`nport',`[Box: box `$1'
  r = ifelse(`$6',,2.0,`$6')
  plg = ifelse(`$7',,`dimen_/4',`$7')
#                           `West side'
  define(`m4n',`ifelse(`$2'`$3'`$4'`$5',,1,`$2',,0,`($2)')')
  d = Box.ht/(m4n*(r+1)+1)
  move to Box.nw+(0,-d); down_
  m4portpins(-plg,d*r,d,W,`$8')
#                           `North side'
  ifelse(`$3',,,`define(`m4n',`($3)')
  d = Box.wid/(m4n*(r+1)+1)
  move to Box.nw+(d,0); right_
  m4portpins(plg,d*r,d,N,`$8')')
#                           `East side'
  define(`m4n',`ifelse(`$2'`$3'`$4'`$5',,1,`$4',,0,`($4)')')
  d = Box.ht/(m4n*(r+1)+1)
  move to Box.ne+(0,-d); down_
  m4portpins(plg,d*r,d,E,`$8')
#                           `South side'
  ifelse(`$5',,,`define(`m4n',`($5)')
  d = Box.wid/(m4n*(r+1)+1)
  move to Box.sw+(d,0); right_
  m4portpins(-plg,d*r,d,S,`$8')')
  `$9']')
define(`m4portpins',`for_(1,m4n,1,
 `{ if (`$1' != 0) then { line to rvec_(0,`$1') }
   `$4'`'m4x`'a: ifelse(xtract(`$5',N),N,Here,`dot') }
  move to rvec_(`$2',0)
  { if (`$1' != 0) then { line to rvec_(0,`$1') }
   `$4'`'m4x`'b: ifelse(xtract(`$5',N),N,Here,`dot') }
  ifelse(m4x,m4n,,`move to rvec_(`$3',0)')')')

                          `gyrator(box specs,space ratio,pin lgth,style)
                           Gyrator two-port wrapper for nport
                           e.g. gyrator(ht boxwid invis,,0,N)'
define(`gyrator',
 `define(`m4dna_',ifelse(xtract(`$4',V)`'xtract(`$4',H),,H`$4',`$4'))dnl
  sc_draw(`m4dna_',H,
   `nport(ifelse(`$1',,wid boxht,`$1'),1,,1,,`$2',`$3',`$4',
      line from (Box,W1a)+(-Box.wid/2,0) \
        left -Box.wid/4 then down W1a.y-W1b.y then right -Box.wid/4
        arcd(Box+(-Box.wid/4,0),(W1a.y-W1b.y)/3,-90,-270)
      line from (Box,W1a)+(Box.wid/2,0) \
        left Box.wid/4 then down W1a.y-W1b.y then right Box.wid/4
        arcd(Box+(Box.wid/4,0),(W1a.y-W1b.y)/3,90,270)
     `$5')')dnl
  sc_draw(`m4dna_',V,
   `nport(ifelse(`$1',,wid boxht,`$1'),,1,,1,`$2',`$3',`$4',
      line from (N1a,Box)+(0,-Box.ht/2) \
        down -Box.ht/4 then right N1b.x-N1a.x then up -Box.ht/4
        arcd(Box+(0,-Box.ht/4),(N1b.x-N1a.x)/3,-90+90,-90+270)
      line from (N1a,Box)+(0,Box.ht/2) \
        down Box.ht/4 then right N1b.x-N1a.x then up Box.ht/4
        arcd(Box+(0,Box.ht/4),(N1b.x-N1a.x)/3,90+90,90+270)
     `$5')') ')

                                `nullator(linespec, wid, ht)'
define(`nullator',`eleminit_(`$1')
   define(`m4wd',ifelse(`$2',,`dimen_/2',`($2)'))dnl
   define(`m4ht',ifelse(`$3',,`dimen_/4',`($3)'))dnl
   {line to rvec_(max(0,rp_len/2-m4wd/2),0)
    move to rvec_(m4wd/2,0)
    { spline ifdpic(0.58) from rvec_(ifdpic(0,-m4wd/20),m4ht/2) \
      to rvec_(m4wd/20*3,m4ht/2) \
      then to rvec_(m4wd/2,m4ht/4) \
      then to rvec_(m4wd/2,-m4ht/4) \
      then to rvec_(m4wd/20*3,-m4ht/2) \
      then to rvec_(-m4wd/20*3,-m4ht/2) \
      then to rvec_(-m4wd/2,-m4ht/4) \
      then to rvec_(-m4wd/2,m4ht/4) \
      then to rvec_(-m4wd/20*3,m4ht/2) \
      then to rvec_(ifdpic(0,m4wd/20),m4ht/2)
      }
    line from rvec_(m4wd/2,0) \
          to rvec_(max(0,rp_len/2),0)}
  {[box invis ht_ m4ht wid_ m4wd] at rvec_(rp_len/2,0)}
   line to rvec_(rp_len,0) invis ')
                                `norator(linespec, wid, ht)'
define(`norator',`eleminit_(`$1')
   define(`m4wd',ifelse(`$2',,`dimen_/2',`($2)'))dnl
   define(`m4ht',ifelse(`$3',,`dimen_/4',`($3)'))dnl
   {line to rvec_(max(0,rp_len/2-m4wd/2),0)
    move to rvec_(m4wd/2,0)
    for i=-1 to 1 by 2 do { {
      spline to rvec_(i*m4wd/4,m4ht/2) \
      then to rvec_(i*m4wd/2,m4ht/2) \
      then to rvec_(i*m4wd/2,-m4ht/2) \
      then to rvec_(i*m4wd/4,-m4ht/2) \
      then to Here } }
    line from rvec_(m4wd/2,0) \
          to rvec_(max(0,rp_len/2),0)}
  {[box invis ht_ m4ht wid_ m4wd] at rvec_(rp_len/2,0)}
   line to rvec_(rp_len,0) invis ')

                    `n-terminal box
                     nterm(box specs; other commands,
                       nw,nn,ne,ns,
                       pin lgth,style,other commands)
                     The default is three-terminal.  Args 2 to 5 are
                     the number of pins to be drawn on W, N, E, S sides.
                     The pins are named by side and number, e.g. W1, W2, N1, ...
                     Arg 6 is the pin length.  Set arg 7 to N to omit the dots
                     on the pins. Arguments 1 and 8 allow customizations, e.g.
                     nterm(,,,,,,N,
                           "$a$" at Box.w ljust
                           "$b$" at Box.e rjust
                           "$c$" at Box.s above) '
define(`nterm',`[Box: box ifelse(`$1',,wid dimen_ ht dimen_*2/3,`$1')
  plg = ifelse(`$6',,`dimen_/4',`$6')
#                           `West side'
  define(`m4n',`ifelse(`$2'`$3'`$4'`$5',,1,`$2',,0,`($2)')')
  d = Box.ht/(m4n+1)
  move to Box.nw+(0,-d); down_
  m4termpins(-plg,d,W,`$7')
#                           `North side'
  ifelse(`$3',,,`define(`m4n',`($3)')
  d = Box.wid/(m4n+1)
  move to Box.nw+(d,0); right_
  m4termpins(plg,d,N,`$7')')
#                           `East side'
  define(`m4n',`ifelse(`$2'`$3'`$4'`$5',,1,`$4',,0,`($4)')')
  d = Box.ht/(m4n+1)
  move to Box.ne+(0,-d); down_
  m4termpins(plg,d,E,`$7')
#                           `South side'
  define(`m4n',`ifelse(`$2'`$3'`$4'`$5',,1,`$5',,0,`($5)')')
  d = Box.wid/(m4n+1)
  move to Box.sw+(d,0); right_
  m4termpins(-plg,d,S,`$7')
  `$8']')
define(`m4termpins',`for_(1,m4n,1,
 `{ if (`$1' != 0) then { line to rvec_(0,`$1') }
   `$3'`'m4x: ifelse(xtract(`$4',N),N,Here,`dot') }
  ifelse(m4x,m4n,,`move to rvec_(`$2',0)')')')

                          `speaker(U|D|L|R|degrees, vert size, type)
                           type=H horn'
define(`speaker',`[setdir_($1,R)
  define(`m4v',`ifelse(`$2',,`dimen_/3',`($2)/4')')dnl
  define(`m4h',`m4v*sqrt(2)')dnl
 ifelse(`$3',H,
  `{H1: line from rvec_(m4h,m4v/2) \
          to rvec_(m4h*3/2,m4v*7/8) \
    then to rvec_(m4h*3/2,-m4v*7/8) \
      then to rvec_(m4h,-m4v/2)}',
  `{H1: line from rvec_(m4h,m4v) \
          to rvec_(m4h*2,m4v*2) \
    then to rvec_(m4h*2,-m4v*2) \
      then to rvec_(m4h,-m4v)}')
 {lbox(m4h,m4v*2)}
 {Box: box invis ht_ m4v*2 wid_ m4h at rvec_(m4h/2,0)}
  In1: rvec_(0,m4v/2)
  In2: Here
  In3: rvec_(0,-m4v/2)
  In4: rvec_(m4h/4,m4v)
  In5: rvec_(m4h*3/4,m4v)
  In6: rvec_(m4h/4,-m4v)
  In7: rvec_(m4h*3/4,-m4v)
  `$4'; resetdir_ ]')

                                `bell(U|D|L|R|degrees, vert size)'
define(`bell',`[setdir_($1,R)
  define(`m4h',`ifelse(`$2',,`dimen_/2',`($2)')')dnl
 {lbox(m4h,m4h)}
 {Box: box invis ht_ m4h wid_ m4h at rvec_(m4h/2,0)}
 {Circle: circle diameter m4h at rvec_(m4h*3/2,0)}
  In1: rvec_(0,m4h/4)
  In2: Here
  In3: rvec_(0,-m4h/4)
  `$3'; resetdir_ ]')
                                `microphone(U|D|L|R|degrees, vert size)'
define(`microphone',`[setdir_($1,R)
  define(`m4h',`ifelse(`$2',,`dimen_/2',`($2)')')dnl
 {L1: line from rvec_(m4h,-m4h/2) \
          to rvec_(m4h,m4h/2)}
 {Circle: circle diameter m4h at rvec_(m4h/2,0)}
  In1: rvec_(m4h*(2-sqrt(3))/4,m4h/4)
  In2: Here
  In3: rvec_(m4h*(2-sqrt(3))/4,-m4h/4)
  `$3'; resetdir_ ]')
                                `buzzer(U|D|L|R|degrees, vert size,[C])'
define(`buzzer',`[setdir_($1,R)
 ifelse(`$3',,
 `define(`m4h',`ifelse(`$2',,`dimen_/2',`($2)')')dnl
   {L1: line from rvec_(m4h,0) \
          to rvec_(m4h,m4h/2) \
     then to rvec_(0,m4h/2) \
      then to rvec_(0,-m4h/2) \
     then to rvec_(m4h,-m4h/2) \
      then to rvec_(m4h,0)}
   {Box: box invis ht_ m4h wid_ m4h at rvec_(m4h/2,0)}
   {L2: line from rvec_(m4h,m4h/2) \
          to rvec_(m4h,m4h/2)+vec_(Rect_(m4h,-75))}
   In1: rvec_(0,m4h/4)
   In2: Here
   In3: rvec_(0,-m4h/4)',
 `$3',C,`define(`m4h',`ifelse(`$2',,`(dimen_/3)',`(($2)/2)')')dnl
   {Face: line from rvec_(m4h,-m4h) \
          to rvec_(m4h,m4h)}
   {arc ccw from Face.end to Face.start with .c at Face.c}
   In1: rvec_(m4h-sqrt(m4h^2-(m4h/3)^2),m4h/3)
   In2: Here
   In3: rvec_(m4h-sqrt(m4h^2-(m4h/3)^2),-m4h/3)')
 `$4'; resetdir_ ]')
                                `earphone(U|D|L|R|degrees, size, [C][R])
                                 earphone pair if arg3 contains C'
define(`earphone',`[ setdir_($1,R)
  define(`m4h',`ifelse(`$2',,`dimen_',`($2)')')dnl
  ifinstr(`$3',C,
   `L: circle diam m4h*0.4
    R: circle diam m4h*0.4 at L+vec_(m4h,0)
    C: 0.5 between L and R
    N: C+(vscal_(m4h/2,Vperp(L,R)))
    Lx: Cintersect(L,L.rad,C,m4h/2,`$3')
    Rx: Cintersect(C,m4h/2,R,R.rad,`$3')
    arc ifinstr(`$3',R,c)cw rad m4h/2 from Lx to Rx with .c at C',
   `{lbox(m4h/3,m4h/2)}
    {Box: box invis ht_ m4h/2 wid_ m4h/3 at rvec_(m4h/6,0)}
    {L1: line thick 2*linethick from rvec_(m4h/3+linethick pt__,-m4h/3) \
           to rvec_(m4h/3+linethick pt__, m4h/3) }
    In1: rvec_(0,m4h/8)
    In2: Here
    In3: rvec_(0,-m4h/8)')
  `$4'; resetdir_ ]')
                               `Signal-flow graph macros: labeled node,
                                directed labeled chopped straight line,
                                directed labeled chopped arc, and a self
                                loop.  All are contained in [] blocks.'

                               `Signal-flow graph initialization macro
                         sfg_init(line len, node rad, arrowhd len, arrowhd wid)'
ifdef(`sfg_init',,
`define(`sfg_init',`cct_init
  sfg_wid = ifelse(`$1',,`(linewid/0.75*(2.5+0.25)/4)',(`$1'))# default line len
  sfg_rad = ifelse(`$2',,(0.25/4/2),(`$2'))  # node radius
  sfg_aht = ifelse(`$3',,(0.25/4),(`$3'))    # arrow height (arrowhead length)
  sfg_awid = ifelse(`$4',,`sfg_aht',(`$4'))  # arrowhead width
  ')')
                               `sfgline(linespec,
                                        text,sfgabove|sfgbelow|ljust|rjust,
                                        attributes)
                                Draw a straight line with linespec, chopped by
                                node radius, with optional label'
define(`sfgline',`eleminit_(`$1',sfg_wid)
[ L1: line to rvec_(rp_len,0) chop sfg_rad `$4'
Start: last line.start
End: Here
  move to last line.c
  ifelse(ifinstr(`$4',->,T,`$4',<-,T),,
   `{ arrow m4c_l ht sfg_aht wid sfg_awid from rvec_(-sfg_aht/2,0) \
        to rvec_(sfg_aht/2,0) }')
  ifelse(`$2',,,`"iflatex(`$ `$2'$',` $2')" ifelse(`$3',,`sfgabove',`$3')')
  ] with .Start at rvec_(sfg_rad,0)
  move to last [].End
  ')
                               `Like above_ or below_ but adding extra space
                                to put text above or below arrowheads or nodes'
define(`sfgabove',`at Here+(0,sfg_awid/2) above')
define(`sfgbelow',`at Here+(0,-sfg_awid/2) below')

                               `sfgnode(at pos,text,above_,circle options)
                                Node: a white circle, possibly labelled. The
                                default label position is inside if the
                                diameter is bigger than textht and textwid'
define(`sfgnode',
 `[C: circle fill_(1) rad sfg_rad ifelse(`$4',,`thickness 0.5',`$4')] with .c \
    ifelse(`$1',,`at rvec_(sfg_rad,0)',`$1')
  move to last [].c
  ifelse(`$2',,,
   `if 2*sfg_rad > Max(textwid,textht,10pt__) \
       then { {"iflatex(`$ `$2'$',` $2')" `$3'} } \
    else { {"iflatex(`$ `$2'$',` $2')" ifelse(`$3',,`sfgabove',`$3')} }')
  ')
                               `sfgarc(linespec,label,above_,cw|ccw,sfact)
                                An arc between nodes at the endpoints of the
                                linespec.  The resulting positions Start, End,
                                C (arc center) and M (arc midpoint) are defined.
                                The fifth argument scales the arc height above
                                its chord.'
define(`sfgarc',`eleminit_(`$1',sfg_wid)
[ Start: Here
  End: Start + vec_(rp_len,0)
    chordht = (rp_len/sqrt(2)-rp_len/2)ifelse(`$5',,,`*($5)')
    arcrd = (chordht^2+(rp_len)^2/4)/chordht/2
  C: 0.5 between Start and End; C: C+vec_(0,ifelse(`$4',ccw,,-)(arcrd-chordht))
  M: C + vec_( 0,ifelse(`$4',ccw,-)arcrd)
  ifelse(ifinstr(`$1',->,T)ifinstr(`$1',<-,T),,
   `arc -> m4c_l ifelse(`$4',ccw,ccw,cw) \
      from Cintersect(Start,sfg_rad,C,arcrd,ifelse(`$4',ccw,R)) \
      to Cintersect(C,arcrd,M,sfg_aht/2,ifelse(`$4',ccw,,R)) \
      ht sfg_aht wid sfg_awid with .c at C
    arc m4c_l ifelse(`$4',ccw,ccw,cw) from M \
      to Cintersect(C,arcrd,End,sfg_rad,ifelse(`$4',ccw,R)) with .c at C',
   `arc m4c_l patsubst(patsubst(`$1',.*<-,<-),->.*$,->) ifelse(`$4',ccw,ccw,cw)\
      from Cintersect(Start,sfg_rad,C,arcrd,ifelse(`$4',ccw,R)) \
      to Cintersect(C,arcrd,End,sfg_rad,ifelse(`$4',ccw,R)) with .c at C')
  ifelse(`$2',,,`{move to M; "iflatex(`$ `$2'$',` $2')" ifelse(`$3',,
   `sfgabove',`$3')}')
  ] with .Start at last line.start
  move to last line.end
  ')
                `sfgself(at position,U|D|L|R|degrees,label,above_,cw|ccw,sfact,
                         [-> | <- | <->])
                                A teardrop-shaped self-loop drawn at "angle"
                                degrees from "positon". The resulting Origin
                                and M (arc midpoint) are defined.  The sixth
                                argument scales the loop. The seventh puts
                                the arrowhead at the beginning, end, or both'
define(`sfgself',`[ Origin: Here
  setdir_(`$2',U)
  d = ifelse(`$6',,,`($6)*') sfg_wid/2; d = d * max(1,sfg_rad/(0.3605*d))
  { m4sfgselfcurve(-,
      ifelse(`$5',ccw,`ifinstr(`$7',<-,<-)',`ifinstr(`$7',->,<-)'))
    M: Here
    ifelse(`$7',,`{ arrow m4c_l from rvec_(0,ifelse(`$5',cw,,-)sfg_aht/2) \
           to rvec_(0,ifelse(`$5',cw,-)sfg_aht/2) ht sfg_aht wid sfg_awid }')
    ifelse(`$3',,,
     `"iflatex(`$ `$3'$',` $3')" ifelse(`$4',,`sfgabove',`$4')') }
  m4sfgselfcurve(,
      ifelse(`$5',ccw,`ifinstr(`$7',->,<-)',`ifinstr(`$7',<-,<-)'))
  resetdir_ ] with .Origin ifelse(`$1',,at Here,`$1')
  move to last [].Origin
  ')
define(`m4sfgselfcurve',`spline `$2' m4c_l from rvec_(Rect_(sfg_rad,`$1'30)) \
  to rvec_(0.3*d,`$1'0.2*d) \
      then to rvec_(0.6*d,`$1'0.35*d) \
  then to rvec_(0.9*d,`$1'0.35*d) \
  then to rvec_(d,`$1'0.2*d) \
      then to rvec_(d,0)')

                     `winding(L|R,diam, pitch, nturns, core wid, core color )
                      The complete spline is drawn, then parts of it are
                      overwritten with the background color (default
                      white).  Arg 1 contains R for right-handed winding.
                      Arg 4 must be an integer.
                      Arg 6 must be compatible with the postprocessor.
                      Requires a recent version of dpic or gpic'
define(`winding',`[ define(`m4rt',`ifinstr(`$1',R,-)')
  d = ifelse(`$2',,`dimen_',`$2')
  p = ifelse(`$3',,d/4,`$3')
  define(`m4n0',`ifelse(`$4',,1,`eval(`$4'-1)')')dnl
  w = ifelse(`$5',,d*3/4,`$5')
  W: spline from (0,0) to (0,0) dnl
  for_(0,m4n0,1,
   `then to vec_(m4rt`'(m4x*p),d) \
    then to vec_(m4rt`'(m4x*p+p/2),d) \
    then to vec_(m4rt`'(m4x*p+p/2),0)`'ifelse(m4x,m4n0,,` \
    then to vec_(m4rt`'(m4x*p+p),0) \')')
  if w > 0 then {
    dx = sign(p)*(linethick+0.5)/2 bp__
    vx = p*min(w/d/8+dx/p,0.25)
    for i=0 to m4n0 do {
      line color ifelse(`$6',,rgbstring(1,1,1),m4lstring(`$6',"`$6'")) \
        thick max(w/(1bp__)-linethick,0) \
        from vec_(m4rt`'(i*p-dx),d/2) \
          to vec_(m4rt`'(i*p+vx),d/2)
      dx = vx }
    }
  T1: W.ifinstr(`$1',R,end,start)
  T2: W.ifinstr(`$1',R,start,end)
  `$7']')

                     `tstrip(U|D|L|R|degrees, n, chars)
                      Terminal strip
                      n=integer number of terminals (default 4)
                      chars:
                       I=invisible terminals
                       C=circle terminals (default)
                       D=dot terminals
                       O=omitted internal lines
                       wid=val; total strip width
                       ht=val; strip height '
define(`tstrip',`[ setdir_(`$1')
  define(`m4n',`ifelse(`$2',,4,`eval($2)')')dnl
  ifelse(eval(m4n<1),1,`define(`m4n',1)')dnl
  setkey_(`$3',ht,dimen_/2)dnl
  setkey_(`$3',wid,m4n*m4ht*0.6)dnl
  {Box: [shade(1,lbox(m4wid,m4ht))] }
  bw = m4wid/(m4n)
  ifinstr(`$3',O,,`for i=1 to m4n-1 do {
   {move to rvec_(i*bw,-m4ht/2); line to rvec_(0,m4ht)}}')
  for_(1,m4n,1,`{T`'m4x: ifinstr(`$3',I,`rvec_((m4x-0.5)*bw,0)',
   `dot(at rvec_((m4x-0.5)*bw,0),,ifinstr(`$3',D,0,1))')
    {L`'m4x: T`'m4x+vec_(0,m4ht/2)}; {R`'m4x: T`'m4x+vec_(0,-m4ht/2)} }')
  `$4' popdef(`m4ht')popdef(`m4ht')
  resetdir_ ]')

                     `jack(U|D|L|R|degrees, chars)
                      Phone jack; arg1 sets drawing direction
                      chars:
                       L|LM|LB|LMB=long and aux contacts; M|B make|break arrows
                       S|SM|SB|SMB=short and aux contacts; M|B make|break arrows
                       R=right orientation with respect to drawing direction '
define(`jack',`[ setdir_(`$1')
  define(`dna_',`ifelse(`$2',,L,`$2',R,L,`$2')')dnl
  s=ifinstr(dna_,R,-1,1)
  ght = dimen_/2
  {Sleeve: [shade(1,lbox(dimen_/12,ght))] }
  G: Sleeve+vec_(0,-ght/2*s)
  F: Sleeve+vec_(dimen_/24,0)
  aht = dimen_/8
  Q: Sleeve+vec_(-dimen_*0.7,s*(ght*0.45-aht*3))
  define(`m4jbm',) m4auxcontacts(`dna_',L,s,)
  Q: Sleeve+vec_(-dimen_*0.7,(aht*3-ght*0.45)*s)
  define(`m4jbm',) m4auxcontacts(`dna_',S,-s,)
  `$3'; resetdir_ ] ')

define(`m4auxcontacts',`ifinstr($1,$2,
 `define(`m4I_',index($1,$2))dnl
  define(`m4abm',ifelse(substr($1,incr(m4I_),1),M,
    M`'ifelse(substr($1,eval(2+m4I_),1),B,B),
    substr($1,incr(m4I_),1),B,
    B`'ifelse(substr($1,eval(2+m4I_),1),M,M)))dnl
  define(`$1',substr($1,0,m4I_)`'substr($1,eval(m4I_+len(m4abm)+1)))dnl
  cht = aht*ifelse(ifinstr(m4jbm,M,T)`'ifinstr(m4abm,B,T),TT,3.9,3)
  Z: jackcontact(ifelse(`$2',S,0.5,0.6)*dimen_,m4abm`'ifelse($4,,,H),$3) \
    with .T at Q+vec_(0,$3*cht)
  $2`'$4: Z.T; Q: $2`'$4 define(`m4jbm',m4abm)
  ifinstr(m4abm,M, $2`'M`'$4: Z.M) ifinstr(m4abm,B,; $2`'B`'$4: Z.B)
  m4auxcontacts(`$1',$2,$3,ifelse($4,,1,`incr($4)'))')')

                     `jackcontact(length,chars,sign)
                      Phone jack contact to left
                      chars:
                       R: right orientation to drawing direction
                       M|B: make|break contact arrows '
define(`jackcontact',`[ Point: (0,0)
  line from Point ifinstr(`$2',H,`-vec_(dimen_/10,0)',
   `to vec_(-dimen_/16,neg_(`$3')*dimen_/16) \
    then to vec_(-dimen_/8,0) then') \
         to vec_(neg_(`$1'),0)
  T: dot(,,1)
  C: T+vec_(dimen_/5,0)
  ifinstr(`$2',H,`
    Connector: [shade(1,lbox(dimen_/24,cht))] \
      at T+vec_((`$1')-dimen_*0.16,neg_(`$3')*cht/2)')dnl
  ifinstr(`$2',M,`
    M: C+vec_(0,`$3'*aht*1.9)
    arrow m4c_l <- ht aht wid aht from C+vec_(0,`$3'*aht*0.4) \
      to M ')dnl
  ifinstr(`$2',B,`
    B: C+vec_(0,neg_(`$3')*aht*1.5)
    arrow m4c_l <- ht aht wid aht from C to B ') ; `$4' ] ')

                     `plug(U|D|L|R|degrees, chars)
                      Phone plug; arg1 sets drawing direction
                      chars:
                       2|3= two|three conductor
                       R= right orientation wrt drawing direction '
define(`plug',`[ setdir_(`$1')
  s=ifinstr(`$2',R,-1,1)
  ght = ifinstr(`$2',3,`dimen_*0.5',`dimen_*0.4')
  A: Here
  AA: line to rvec_(dimen_*0.3,0) \
      then to rvec_(dimen_*0.3,s*ght/3) \
    then to rvec_(dimen_*0.7,s*ght/3); TA: dot(,,1)
  ifinstr(`$2',3,`
    C: A+vec_(0,s*ght/2)
    TC: line from C to C+vec_(dimen_*0.6,0); TC: Here
    B: 2 between A and C',`B: A+vec_(0,s*ght)')
  BB: line from B to B+vec_(dimen_*0.3,0) \
    then to B+vec_(dimen_*0.3,-s*ght/3) \
    then to B+vec_(dimen_*0.6,-s*ght/3); TB: Here
  `$3'; resetdir_ ]')

                     `A dabble in quantum circuits:
                      SQUID(n,diameter,initial angle,cw|ccw)
                      Superconducting quantum interface device with
                      n junctions labeled J1, ... Jn placed around a
                      circle with initial angle -90 deg (by default)
                      with respect to the current drawing direction. The
                      default diameter is dimen_'
define(`SQUID',
`[ define(`m4sqn',`ifelse(`$1',,2,`$1')')dnl
 define(`m4ssz',`ifelse(`$2',,`dimen_',`$2')')dnl
 define(`m4sof',`ifelse(`$3',,-90,`$3')')dnl
 define(`m4ssg',`ifelse(`$4',,+,`$4',ccw,+,-)(m4x-1)/(m4sqn)*360')dnl
 define(`m4sxlen',C.rad/4)dnl

 C: circle diam m4ssz
 for_(1,m4sqn,1,
  `move to C+vec_(Rect_(C.rad,m4sof`'m4ssg))
   J`'m4x: Here
   { line from rvec_(Rect_(m4sxlen,m4sof`'m4ssg+45)) \
            to rvec_(Rect_(m4sxlen,m4sof`'m4ssg+225)) }
   { line from rvec_(Rect_(m4sxlen,m4sof`'m4ssg-45)) \
            to rvec_(Rect_(m4sxlen,m4sof`'m4ssg-225)) }')
 `$5' ]')

`==============================================================================
                                Customizations:
                                The size and style parameters below can be
                                tweaked, and the cct_init macro modified.'

                                Size and style parameters:
define(`dimen_',`linewid')           Default element body size unit

define(`sourcerad_',`(0.25*dimen_)') Source element default radius
define(`csdim_',`(0.3*dimen_)')      Controlled Source width/2
define(`elen_',`(1.5*dimen_)')       Default element length
define(`delay_rad_',`(0.35*dimen_)') Delay elements
define(`dotrad_',`(0.04*dimen_)')    Redefine dot size for circuits
define(`m4fill',0)                 Default fill for diode, fuse, ...
define(`em_arrowwid',`(dimen_/9)')  `em_arrows arrowhead width'
define(`em_arrowht',`(dimen_/7)')   `em_arrows arrowhead ht'
define(`em_arrowhead',1)            `em_arrows arrowhead style'

right_
divert(0)dnl