anchor.diff:    )
   
   
  +(defclass collision-rectangle ()
  +  ((center-point :initarg :center-point :type vec3)
  +   (radius :initarg :radius :type vec3)))
  +
   ;; TODO: give nice print representation
   ;; TODO: make super-class rectangle and sub-class game-object. Seperating rendering
   ;;       representation from interior representation and proxy geometry for collision
   ;;       tests
  +;; UPDATE: maybe go with the superclass: rectangle, subclass: game-object which will contain
  +;;         a representation point (e.g. filled with sphere, rectangle), an <animation> slot
  +;;         a proxy geometry, a cached geometry (past timesteam when no collision orientation)
   (defclass rectangle ()
     ;; TODO: instead of vec2 provide as seperate x1-x x1-y ? So that
     ;;       transforming into 1d-array is easier (to pass into foreign-array)
  
positive.code: 		   :x1 x1
  		   :x2 x2
  		   :y1 y1
  		   :y2 y2)))
  
  (defun make-rectangle (&optional
  			 (x 0.0)
  
negative.code: 
  ;; TODO: add texture coordinate to initilizations, providing a texture.png
  ;; and a fixed texture coordinate with texatl:with-sprite ?
  ;; UPDATE: maybe go with the superclass: rectangle, subclass: game-object which will contain
  ;;         a representation point (e.g. filled with sphere, rectangle), an <animation> slot
  ;;         a proxy geometry, a cached geometry (past timesteam when no collision orientation)
  (defun make-rectangle-c (&optional
  			   (center-point (vec3 0.0 0.0 0.0))
  			   (radius (vec3 50.0 50.0 0.0)))
  