anchor.diff:    (setf (x vec) (/ (x vec) n))
     (setf (y vec) (/ (y vec) n)))
   
  -
   (defun mag-vectors (vec)
     (sqrt (+ (* (x vec) (x vec))
   	   (* (y vec) (y vec)))))
  
positive.code: (defparameter *height* 400)
  (defparameter *location* nil)
  (defparameter *velocity* nil)
  (defparameter *mouse* nil)
  (defparameter *center* nil)
  
  
negative.code:     (if (zerop m)
  	0
  	(div-vectors vec m))))
  
  (defun limit-vectors (vec limit)
    (if (> (x vec) limit)
        (setf (x vec) limit))
  
    (if (> (y vec) limit)
        (setf (y vec) limit)))
  
  
  (defun help ()
    (format t "Vectors~%")
  