anchor.diff:    (do-objects (player :type 'player)
       (player-die player)))
   
  +(defun enemy-die (enemy)
  +  (setf (death-tick enemy) 0)
  +  (do-objects (player :type 'player)
  +    (increment-score (floor (score player) 10) player)))
  +
    
   ;;;; Game
  
positive.code: ;;;; Player
  
  (defconstant player-movement-steps 3)
  
  (defclass player ()
    ((pos :accessor pos)
  
negative.code:          (setf (movement-actions player) '()))
          (t (outer-world))))
  
  (defun increment-score (increment player)
    (symbol-macrolet ((score (score player)))
      (let ((new-score (+ score increment)))
        (when (/= (floor new-score player-life-bonus)
                  (floor score player-life-bonus))
          (incf (lives player)))
        (setf score new-score))))
  
  
  ;;;; Enemy
  