anchor.diff:  (defparameter *gameboard* (make-array '(20 20)))
   (defparameter *player* (make-instance 'player :y 10 :x 10 :color *random-color*))
   (defparameter *mob* (list (make-instance 'mob :x (random 200) :y (random 200))))
  -(defparameter *grass-tile* (make-instance 'tile :sprite *grass-sprite*))
  +(defparameter *grass-tile* (make-instance 'tile :sprite nil))
   
   (defun get-player-location ()
     (values (x-pos *player*) (y-pos *player*)))
  
positive.code:              (:quit-event () (on-quit-event))
               (:key-down-event (:key key) (on-key-down-event key))
               (:mouse-button-down-event (:button button) (on-button-down-event button))
               (:idle () (on-idle-event)))))))
negative.code:   (sdl:enable-unicode)
    (sdl-ttf:init-ttf)
    (sdl:enable-key-repeat 500 150)
    (setf (sprite *grass-tile*) (sdl:load-image *grass-sprite-path*)))
  
  (defun draw ()
    "This code is looped repeatedly while main is run. The order of drawing code is important."
  