%!PS-Adobe-2.0
%%BoundingBox: 0 0 372 180

/w 372 def
/h 180 def

1 setlinejoin
1 setlinecap

(ps3d.inc) run
(cube.inc) run
(epsetup.inc) run

[-0.25 1 1 0 ] set-light

/sc 32 def

[0 0 6 1] set-eye
/dA 8 def
/A 17 120 add def
/dA 10 def

[0 1 0] A rotate3d

 { 

page-begin

/E get-virtual-eye def
/L get-virtual-light def

/red [ 1 0 0 ] def
/pink [ 0.6 0.6 1.0] def

E 2 get 0 gt {
  /shift0 -1 def
  /shift1 1 def
  /c0 red def
  /c1 pink def
}{
  /shift0 1 def
  /shift1 -1 def
  /c1 red def
  /c0 pink def
} ifelse

gsave3d
0 -0.5 0 translate3d
0 0 shift0 translate3d
/E0 get-virtual-eye def
newpath
cube {
  % [ polygon normal ]
  aload pop 
  /N exch def
  /P exch def
  N E0 dot-product 0 ge {
    P P length 1 sub get 
    aload pop moveto3d
    P {
      aload pop lineto3d
    } forall
    gsave
    /s L N dot-product 
    [0.30 0.30 0.80 1] shade def
    c0 0 get s mul c0 1 get s mul c0 2 get s mul setrgbcolor 
    fill
    grestore
    stroke
  } if
} forall
grestore3d

gsave3d
0 -0.5 0 translate3d
0 0 shift1 translate3d
/E1 get-virtual-eye def
newpath
cube {
  % [ polygon normal ]
  aload pop 
  /N exch def
  /P exch def
  N E1 dot-product 0 ge {
    P P length 1 sub get 
    aload pop moveto3d
    P {
      aload pop lineto3d
    } forall
    gsave
    /s L N dot-product 
    [0.30 0.30 0.80 1] shade def
    c1 0 get s mul c1 1 get s mul c1 2 get s mul setrgbcolor 
    fill
    grestore
    stroke
  } if
} forall
grestore3d

page-end

[0 1 0 ] dA rotate3d 

} loop