anchor.diff:     (NewtonCreateSphere world  0.5  0  #f)
      (runtime-error "Can't create box" #f)))
   
  -(define spheres (map
  -   (lambda (id)
  -      (let ((x (* id 0.7))
  -            (y (* id 1)))
  -         (NewtonCreateDynamicBody world collision
  -            `(;x y z w
  -               1 0 0 0 ; front
  -               0 1 0 0 ; up
  -               0 0 1 0 ; right
  -
  -               ,(/ (- (rand! 400) 200) 100) ; x
  -               ,(+ (/ id 10) 1)                    ; y
  -               ,(/ (- (rand! 400) 200) 100) ; z
  -               1       ; posit
  -             ))))
  -   (iota 50)))
  +(define spheres null);(map
  +;   (lambda (id)
  +;      (NewtonCreateDynamicBody world collision
  +;         `(;x y z w
  +;            1 0 0 0 ; front
  +;            0 1 0 0 ; up
  +;            0 0 1 0 ; right
  +;
  +;            ,(/ (- (rand! 400) 200) 100) ; x
  +;            ,(+ (/ id 3) 1)             ; y
  +;            ,(/ (- (rand! 400) 200) 100) ; z
  +;            1       ; posit
  +;          )))
  +;   (iota 50)))
   (for-each (lambda (sphere)
      (NewtonBodySetMassProperties sphere 1.0 collision)
      (NewtonBodySetForceAndTorqueCallback sphere ApplyGravity)
   ) spheres)
  -(NewtonDestroyCollision collision)
  +; we need this collision for feature use
  +;(NewtonDestroyCollision collision)
   
   
   ;
  
positive.code:                0 1 0 0 ; up
                 0 0 1 0 ; right
  
                 ,(/ (- (rand! 400) 200) 100) ; x
                 ,(+ id 10)                   ; y
                 ,(/ (- (rand! 400) 200) 100) ; z
                 1       ; posit
               ))))
     (iota 20)))
  (for-each (lambda (cube)
     (NewtonBodySetMassProperties cube 1.0 collision)
     (NewtonBodySetForceAndTorqueCallback cube ApplyGravity)
  
negative.code:          (glVertex3f 0 1 19)
     (glEnd)
  
  ;  (glMaterialfv GL_FRONT GL_DIFFUSE '(1 0 0 1))
     (let ((matrix '(0.1 0.1 0.1 0.1  0.1 0.1 0.1 0.1  0.1 0.1 0.1 0.1  0.1 0.1 0.1 0.1)))
        (for-each (lambda (cube)
           (NewtonBodyGetMatrix cube matrix)
  