anchor.diff:  ;(NewtonBodySetForceAndTorqueCallback rigidBody2 ApplyGravity)
   ;(print "To rigid body added callback")
   
  -(NewtonDestroyCollision collision)
   (print "3.NewtonGetMemoryUsed = " (NewtonGetMemoryUsed))
   
   (define (glCube)
  
positive.code: (define NewtonWorldSetDestructorCallback (dlsym $ type-void "NewtonWorldSetDestructorCallback" type-vptr type-callback))
  
  ;
  (define NewtonCreateBox (dlsym $ type-vptr "NewtonCreateBox" type-vptr type-float type-float type-float type-int+ type-float*))
  (define NewtonCreateDynamicBody (dlsym $ type-vptr "NewtonCreateDynamicBody" type-vptr type-vptr type-float*))
  (define NewtonBodySetForceAndTorqueCallback (dlsym $ type-void "NewtonBodySetForceAndTorqueCallback" type-vptr type-callback))
  (define NewtonBodySetMassProperties (dlsym $ type-void "NewtonBodySetMassProperties" type-vptr type-float type-vptr))
  
negative.code: 
  (define type-callback 61)
  (define type-float* (vm:or type-float #x40))
  (define NewtonWorld* type-vptr)
  (define dFloat* (vm:or type-float #x40))
  
  (define NewtonWorldGetVersion (dlsym $ type-fix+ "NewtonWorldGetVersion"))
  (define NewtonWorldFloatSize  (dlsym $ type-fix+ "NewtonWorldFloatSize"))
  