anchor.diff:  ;;;                     REGION is now a subclass of DESIGN.
   ;;;  2001-01-21  GB     fixed bug in (TRANSFORM-REGION T RECTANGLE-SET)
   ;;;                     added some documentation
  +
  +;;;  GB = Gilbert Baumann <unk6@rz.uni-karlsruhe.de>
  +;;;  AR = Arnaud Rouanet <rouanet@emi.u-bordeaux.fr>
   
   ;;; ---- TODO ----------------------------------------------------------------------------
   
  
positive.code: 
  ;;;  When        Who    What
  ;;; --------------------------------------------------------------------------------------
  ;;;  2001-07-12  GB     fixed bugs in
  ;;;                     (BOUNDING-RECTANGLE* STANDARD-REGION-UNION)
  ;;;                     (BOUNDING-RECTANGLE* STANDARD-REGION-INTERSECTION)
  
negative.code:              (multiple-value-bind (x2* y2*) (transform-position transformation x2 y2)
                 (make-rectangle* x1* y1* x2* y2*)))))
          (t
           (make-polygon (mapcar (lambda (p) (transform-region transformation p)) 
                                 (polygon-points rect)))) ))
  
  (defmethod region-contains-position-p ((self standard-rectangle) x y)
    (multiple-value-bind (x1 y1 x2 y2) (rectangle-edges* self)
  