%!
% Sierpinski gasket
% By John Fouhy.
/maxdepth 10 def
/length 500 def
/xoff 60 def
/yoff 300 def
/root3 1.7320508 def

% draw a (roughly) equilateral triangle
/triangle {
newpath x y moveto a 0 rlineto 120 rotate a 0 rlineto 240 rotate closepath
%%%depth 20 div 0 0 setrgbcolor
stroke } def

% usage: a x y depth rec
% where a is the side length, (x,y) are the coords of the lower left corner, and depth is the recursion depth
/rec {
/depth exch def
/y exch def /x exch def /a exch def
triangle
depth maxdepth lt
{
/newa a 2 div def
/newdepth depth 1 add def
newa x y newdepth
newa x a 4 div add y root3 a mul 4 div add newdepth
newa x newa add y newdepth rec rec rec
}
if
} def

0 setlinewidth
length xoff yoff 1 rec

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