anchor.diff:                                          radius-x 0
                                           0 radius-y))
            (transformed-ellipse (transform-region (medium-transformation medium)
  -                                                ellipse))
  -         (start-angle (ellipse-start-angle transformed-ellipse))
  -         (end-angle (ellipse-end-angle transformed-ellipse)))
  +                                                ellipse)))
       (multiple-value-bind (center-x center-y) (ellipse-center-point* transformed-ellipse)
         (call-next-method medium center-x center-y radius-x radius-y filled))))
   
   (defmethod medium-draw-circle* :around ((medium basic-medium) center-x center-y
  -                                         radius start-angle end-angle fill)
  +                                         radius start-angle end-angle filled)
     (let* ((ellipse (make-elliptical-arc* center-x center-y
                                           radius 0
                                           0 radius
  
positive.code:   )
  
  (defmethod degraft-medium ((medium basic-medium) port sheet)
    (setf (%medium-sheet medium) nil))
  
  (defmethod allocate-medium ((port port) sheet)
  
negative.code: ;;;;;;;;;
  
  (defmethod engraft-medium ((medium basic-medium) port sheet)
    (declare (ignore port))
    (setf (%medium-sheet medium) sheet)
    #||
    (medium-foreground medium) (medium-foreground sheet)
  