anchor.diff:               options))))
   
   (defmethod draw-design (medium (design standard-region-union)
  -			&rest options &key &allow-other-keys)
  +                        &rest options &key &allow-other-keys)
     (map-over-region-set-regions (lambda (region)
                                    (apply #'draw-design medium region options))
                                  design))
   
   (defmethod draw-design (medium (design standard-rectangle-set)
  -			&rest options &key &allow-other-keys)
  +                        &rest options &key &allow-other-keys)
     ;; ### we can do better (faster) than this.
     (map-over-region-set-regions (lambda (region)
                                    (apply #'draw-design medium region options))
  
positive.code:   (setq medium (stream-designator-symbol medium '*standard-output*))
    (with-gensyms (gcontinuation cont-arg)
      `(flet ((,gcontinuation (,cont-arg)
  	      (declare (ignore ,cont-arg))
  	      ,@body))
         (declare (dynamic-extent #',gcontinuation))
         (invoke-with-drawing-options
          ,medium #',gcontinuation ,@drawing-options))))
  
negative.code:   (let ((method-name (symbol-concat '#:medium- name '*)))
      `(eval-when (:execute :load-toplevel :compile-toplevel)
         (defmethod ,method-name ((stream sheet) ,@args)
           (with-sheet-medium (medium stream)
             (,method-name medium ,@args))))))
  
  (def-graphic-op draw-point (x y))
  (def-graphic-op draw-points (coord-seq))
  