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%!
%%BoundingBox: 0 0 236 236
% M. C. Escher style impossible triangle
% written by Guy Shaw
% Things that are easy to play with:
% Position on paper, overall size, and linewidth
/inch { 72 mul } bind def
gsave
.15 inch 0 translate
3 inch dup scale
1 3 inch div setlinewidth
% Thickness parameter:
% /Thick is the thickness of the structural members of the triange,
% as a fraction of the height of the triangle.
% Reasonable looking impossible triangles can be obtained with Thick <= 1/6.
% right at /Thick == 1/6, there is no space left inside the triangle.
% /Thick > 1/6 yields bizarre, but not very interesting results.
% /Thick < 1/20 is less interesting, because the "impossibility"
% is not so striking when the structural members are that thin.
% A good "standard" value is 1/8.
/Thick 1 8 div def
% You would not normally want to change anything that follows.
/Tall 1 def
/HalfThick Thick .5 mul def
newpath
HalfThick Thick moveto
Thick 0 lineto
1 Thick sub 0 lineto
1 HalfThick sub Thick lineto
.5 HalfThick add Tall Thick sub lineto
1 Thick sub 0 moveto
.5 HalfThick add Tall 3 Thick mul sub lineto
Thick 3 mul Thick 2 mul lineto
1 Thick 2.5 mul sub Thick moveto
.5 Tall Thick 4 mul sub lineto
stroke
newpath
HalfThick Thick moveto
1 Thick 2.5 mul sub Thick lineto
HalfThick neg Thick rlineto
Thick Thick add Thick Thick add lineto
.5 HalfThick add Tall Thick sub lineto
Thick neg 0 rlineto
closepath
fill
grestore
/Helvetica findfont 30 scalefont setfont
0 5 moveto (L) show
3.1 inch 5 moveto (R) show
1.6 inch 2.7 inch moveto (T) show
showpage
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