%!PS-Adobe-2.0
%%BoundingBox: 0 0 100 100

/page-begin {
gsave
50 50 translate
/S 32 def
S dup scale
1 S div setlinewidth
1 setlinecap
1 setlinejoin
} def

/page-end {
grestore
showpage
} def

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

(polyhedron.inc) run

/R 2 3 div 2 sqrt mul def

/tetrahedron-vertex [
  [0 0 1]
  [1 0 -1 3 div ]
  [120 cos R mul 120 sin R mul -1 3 div ]
  [240 cos R mul 240 sin R mul -1 3 div ]
] def

/tetrahedron [
[
  [
    tetrahedron-vertex 0 get 
    tetrahedron-vertex 1 get 
    tetrahedron-vertex 3 get 
  ] dup normal-function
]
[
  [
    tetrahedron-vertex 0 get 
    tetrahedron-vertex 2 get 
    tetrahedron-vertex 1 get 
  ] dup normal-function
]
[
  [
    tetrahedron-vertex 0 get 
    tetrahedron-vertex 3 get 
    tetrahedron-vertex 2 get 
  ] dup normal-function
]
[
  [ 
    tetrahedron-vertex 1 get 
    tetrahedron-vertex 2 get 
    tetrahedron-vertex 3 get 
  ] dup normal-function
]
] def

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

[0 0 10 1 ] set-eye
/light [ -0.25 1 0.25 0 ] normalized def
/shading [ 0.4 0.5 1 1 ] def

[1 1 0 ] 45 rotate3d

{
page-begin
/E get-eye cim3d transform3d def
/L light cim3d transform3d def
tetrahedron
polyhedron-draw
page-end
[0 1 0] 10 rotate3d
} loop