anchor.diff:  (NewtonTreeCollisionBeginBuild collision)
   ; пол
   (NewtonTreeCollisionAddFace collision 4 '(
  -   -10 0  10
  -    10 0  10
  -    10 0 -10
  -   -10 0 -10) (* 3 4) 0) ; (* 3 4) is stride, where 4 is sizeof(float)
  +   -9 0.1  9
  +    9 0.1  9
  +    9 0.1 -9
  +   -9 0.1 -9) (* 3 4) 0) ; (* 3 4) is stride, where 4 is sizeof(float)
   ; ступеньки
   (NewtonTreeCollisionAddFace collision 4 '(
      -4 0.6  4
  
positive.code:       0 0 0
        0 1 0)
  
     ; платформа
  ;   (glBegin GL_LINE_STRIP)
     (glBegin GL_QUADS)
        (glColor3f 0.4 0.4 0.4)
        (glVertex3f -10 0  10)
        (glVertex3f  10 0  10)
        (glVertex3f  10 0 -10)
        (glVertex3f -10 0 -10)
        (glColor3f 0.2 0.2 0.2)
        (glVertex3f -4 0.01  4)
        (glVertex3f  4 0.01  4)
        (glVertex3f  4 0.01 -4)
        (glVertex3f -4 0.01 -4)
        (glColor3f 0.5 0.5 0.5)
        (glVertex3f -4 0.6  4)
        (glVertex3f  4 0.6  4)
        (glVertex3f  4 0.6 -4)
        (glVertex3f -4 0.6 -4)
        (glColor3f 0.2 0.2 0.2)
        (glVertex3f -2 0.61  2)
        (glVertex3f  2 0.61  2)
        (glVertex3f  2 0.61 -2)
        (glVertex3f -2 0.61 -2)
        (glColor3f 0.5 0.5 0.5)
        (glVertex3f -2 1.2  2)
        (glVertex3f  2 1.2  2)
        (glVertex3f  2 1.2 -2)
        (glVertex3f -2 1.2 -2)
     ;  (glVertex3f -100 0  100)
     (glEnd)
  
  
     (glBegin GL_LINES)
  
negative.code: 
     (glEnable GL_DEPTH_TEST)
  
     ; http://www.glprogramming.com/red/chapter12.html
     (glEnable GL_LIGHTING)
     (glLightModelf GL_LIGHT_MODEL_TWO_SIDE GL_TRUE)
     (glEnable GL_NORMALIZE)
  
     ; http://compgraphics.info/OpenGL/lighting/light_sources.php
     (glEnable GL_LIGHT0)
     (glLightfv GL_LIGHT0 GL_DIFFUSE '(0.7 0.7 0.7 1.0))
  
     (glEnable GL_COLOR_MATERIAL)
  
     (NewtonInvalidateCache world) ; say "world construction finished"
  
     ; return parameter list:
     (let ((oldtime (gettimeofday)))
     (list oldtime 1 cubes spheres)))
  
  ; draw
  (lambda (oldtime i cubes spheres)
  (let ((newtime (gettimeofday)))
     ; обновим мир
     (let ((ms (* (+ (- (car newtime) (car oldtime)) (/ (- (cdr newtime) (cdr oldtime)) 1000000)) 2)))
        (NewtonUpdate world (if (> ms 0.006) 0.006 ms)))
  
     ; и нарисуем его
     (glClear (vm:or GL_COLOR_BUFFER_BIT GL_DEPTH_BUFFER_BIT))
  
  
     (glMatrixMode GL_MODELVIEW)
     (glLoadIdentity)
  