 
 (defstruct animal x y energy dir genes)
 
-(defparameter *animals*
+(defvar *animals*
   (list (make-animal :x      (ash *width* -1)
                      :y      (ash *height* -1)
                      :energy 1000

(defparameter *width* 80)
(defparameter *height* 30)
(defparameter *jungle* '(45 10 10 10))
(defparameter *plant-energy* 80)

(defparameter *plants* (make-hash-table :test #'equal))

(defun random-plant (left top width height)
  (let ((pos (cons (+ left (random width)) (+ top (random height)))))

      (incf (animal-energy animal) *plant-energy*)
      (remhash pos *plants*))))

(defvar *reproduction-energy* 200)

(defun reproduce (animal)
  (let ((e (animal-energy animal)))
