anchor.diff:  
   
   (defmethod draw-snake ((thesnake snake))
  +  ;; Draw fruit
  +  (gl:color 0.5 0.2 0.3)
  +  (draw-snake-piece *fruit-position*)
     ;; Draw snake
  -  ;;(draw-snake-piece (pos thesnake))
  -  ;; Draw snake pieces
  -  ;;(format t "Snake position: ~a~%" (pos thesnake))
     (gl:color 0.3 0.2 0.5)
     (let ((i 0))
       (loop for piece in (piece-list thesnake)
  
positive.code: 	      (setf *has-snake-moved* t)))))
  
  
    ;;; Collision detection
    ;; With own tail
    ;; So basically we'll only have to do that for the head.
    ;; Just iterate and check if overlapping a piece of your own tail.
  
negative.code: 
  
  (defmethod init-snake ((thesnake snake))
    ;; Spawn fruit
    (setf *fruit-position*
  	(make-vec2 :x (* 3 (/ *window-width* 4.0))
  		   :y (/ *window-height* 16.0)))
    ;; Spawn first pieces
    (loop for x from 0 to *snake-init-num-pieces*
       do (push (make-vec2 :x (- (/ *window-width* 2.0)
  			       (* *snake-piece-size* x))
  