%!PS-Adobe-2.0
%%BoundingBox: 0 0 144 144

72 dup translate

(../../ps/ps3d.inc) run
(sphere.inc) run

% --------------------------------

/sc 64 def
sc dup scale
1 sc div setlinewidth

[0 0 4 1] set-eye
[1 0 0 ] 130 rotate3d

/S 18 sphere def

/E get-eye cim3d transform3d def

/light-source [-0.25 1 0.5 0] normalized def
/L light-source cim3d transform3d def

currentlinewidth 4 div setlinewidth

S {
  aload pop
  /f exch def % f = normal function
  /p exch def % p = array of vertices on the face
  f E dot-product 0 ge {
    newpath
	% move to last point first
    p p length 1 sub get aload pop moveto3d
    p { 
      aload pop
      lineto3d
    } forall
	gsave
	L f dot-product [ 0.2 0.2 0.9 0.9 ] shade 
    setgray
	fill
	grestore
    stroke
  } if 
} forall