anchor.diff:    ;; (compose-transformations A B)x = (A o B)x = ABx
     (with-slots ((dx1 dx) (dy1 dy)) transformation1
       (with-slots ((dx2 dx) (dy2 dy)) transformation2
  -      (make-instance 'standard-translation
  -                     :dx (+ dx1 dx2)
  -                     :dy (+ dy1 dy2)))))
  +      (make-translation-transformation (+ dx1 dx2) (+ dy1 dy2)))))
   
   (defmethod compose-transformations (transformation2
                                       (transformation1 standard-identity-transformation))
  
positive.code:     (values mxx mxy myx myy tx ty)))
  
  (defun make-translation-transformation (dx dy)
    (make-instance 'standard-translation
                   :dx (coordinate dx) :dy (coordinate dy)))
  
  (defun make-rotation-transformation (angle &optional origin)
    (if origin
  
negative.code: ;;;   Created: 1998-09-29
  ;;;    Author: Gilbert Baumann <unk6@rz.uni-karlsruhe.de>
  ;;;   License: LGPL (See file COPYING for details).
  ;;;       $Id: transforms.lisp,v 1.30 2005/11/22 11:40:02 gbaumann Exp $
  ;;; --------------------------------------------------------------------------------------
  ;;;  (c) copyright 1998,1999,2003 by Gilbert Baumann
  ;;;  (c) copyright 2000 by 
  