import three; size(560,320,IgnoreAspect); size3(140,80,15); currentprojection=perspective(-3,20,10,up=Y); currentlight=White; path[] outline; real a=-0.4; real b=0.95; real y1=-5; real y2=-3y1/2; path A=(a,0){dir(10)}::{dir(89.5)}(0,y2); outline.push(A); outline.push((0,y1){dir(88.3)}::{dir(20)}(b,0)); real c=0.5*a; pair z=(0,2.5); path[] text = shift(0,2)*scale(0.01,0.15)* texpath(Label("{\it symptote}",z,0.25*E+0.169S,fontsize(24))); outline.append(text); pair w=(0,1.7); outline.push(intersectionpoint(A,w-1--w)--w); outline.push((0,y1)--(0,y2)); outline.push((a,0)--(b,0)); for(path p : outline) draw(extrude(p,-0.1Z),material(lightgray,shininess=1.0)); draw(path3(outline),red+linewidth(0)); draw(surface(text),red,nolight);