cube.ps

%!PS-Adobe-3.0 EPSF-3.0
%%Pages: 1
%%BoundingBox: 0 0 720 720
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/inch { 72 mul } def

/windistance 1 def

/project3d {
  4 dict begin
    /z exch def
    /y exch def
    /x exch def
    /factor windistance z div def
    x factor mul y factor mul
  end
} def

/moveto3d { project3d moveto } def
/lineto3d { project3d lineto } def

/points [
   0  0.5 sqrt      1.5
  -1  0.5 sqrt      2.0
   0  0.5 sqrt      2.5
   1  0.5 sqrt      2.0
   0  0.5 sqrt neg  1.5
  -1  0.5 sqrt neg  2.0
   0  0.5 sqrt neg  2.5
   1  0.5 sqrt neg  2.0
] def

/point {
  1 dict begin
    /idx exch 3 mul def
    points idx get
    points idx 1 add get
    points idx 2 add get
  end
} def

/side {
  4 dict begin
    /i4 exch def
    /i3 exch def
    /i2 exch def
    /i1 exch def
    newpath
    i1 point moveto3d
    i2 point lineto3d
    i3 point lineto3d
    i4 point lineto3d
    closepath
  end
} def

5 inch dup translate
5 inch dup scale

1 256 div setlinewidth
2 setlinecap
2 setlinejoin

0 1 2 3 side stroke
4 5 6 7 side stroke
0 1 5 4 side stroke
0 3 7 4 side stroke

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