anchor.diff:                     (gl:vertex ex ey)
                      (gl:vertex sx ey)))))))
   
  +(defun disclaim-cells (grid)
  +  (with-weight-computation (:delay grid)
  +    (dotimes (row grid-rows)
  +      (dotimes (col grid-cols)
  +        (symbol-macrolet ((cell (cell-ref row col grid)))
  +          (when (= cell-claiming cell)
  +            (setf cell cell-unclaimed)))))))
  +
   (defun claim-cells (grid)
     (let ((unclaimed-neighbors '()))
       (dotimes (row grid-rows)
  
positive.code: 
  (define-level (consix :test-order '(player enemy t))
    (grid :named grid)
    (player :row (1- grid-rows) :col (floor grid-cols 2) :grid grid)
    (enemy :pos (vec 0 0) :structure (list 0.0 0.0 0.0) :grid grid))
  
  (defun game ()
  
negative.code: 
  (defclass player ()
    ((pos :accessor pos)
     (initial-row :initarg :row :accessor initial-row)
     (initial-col :initarg :col :accessor initial-col)
     (row :initarg :row :accessor row)
     (col :initarg :col :accessor col)
     (grid :initarg :grid :accessor grid)
     (halo :initform (make-instance 'halo) :accessor halo)
     (movement-actions :initform '() :accessor movement-actions)
     (claiming :initform nil :accessor claiming-p)
     (lives :initarg :lives :accessor lives)))
  
  (defmethod initialize-instance :after ((player player) &rest initargs)
    (declare (ignore initargs))
  