anchor.diff:  
   ;;;  When        Who    What
   ;;; --------------------------------------------------------------------------------------
  +;;;  2001-03-09  AR     fixed a bug in MAKE-ELLIPICAL-THING
  +;;;                     fixed STANDARD-ELLIPTICAL-ARC defclass
  +;;;  2001-03-06  AR     fixed bug in (REGION-EQUAL STANDARD-RECTANGLE STANDARD-RECTANGLE)
  +;;;                     REGION is now a subclass of DESIGN.
   ;;;  2001-01-21  GB     fixed bug in (TRANSFORM-REGION T RECTANGLE-SET)
   ;;;                     added some documentation
  -;;;  2001-03-06  AR     fixed bug in (REGION-EQUAL STANDARD-RECTANGLE STANDARD-RECTANGLE)
  -;;;                     REGION is now a subclass of DESIGN.
  -;;;  2001-03-09  AR     fixed a bug in MAKE-ELLIPICAL-THING
  -;;;                     fixed STANDARD-ELLIPTICAL-ARC defclass
  +;;;  2001-07-09  GB     maybe fixed a bug in MAP-OVER-SCHNITT-GERADE/POLYGON.
   
   ;;; ---- TODO ----------------------------------------------------------------------------
   
  
positive.code: ;;;   Created: 1998-12-02 19:26
  ;;;    Author: Gilbert Baumann <unk6@rz.uni-karlsruhe.de>
  ;;;   License: LGPL (See file COPYING for details).
  ;;;       $Id: regions.lisp,v 1.9 2001-03-12 12:00:24 rouanet Exp $
  ;;; --------------------------------------------------------------------------------------
  ;;;  (c) copyright 1998,1999 by Gilbert Baumann
  ;;;  (c) copyright 2001 by Arnaud Rouanet (rouanet@emi.u-bordeaux.fr)
  
negative.code:                                 ((add (lo lu ro ru)
                                     (dolist (s sps
                                               ;; ansonsten
                                               (push (make-pg-splitter :links  (list lu lo) 
                                                                       :rechts (list ru ro))
                                                     sps) )
                                       (when (and (region-equal lo (car (pg-splitter-links s)))
  