anchor.diff:     (compose-space (content-pane content)))
    
    (defmethod compose-space ((box xbox-pane))
  -   (with-slots (contents) box
  +   (with-slots (contents major-spacing) box
        (loop
            for content in contents
            for sr = (content-sr* box content)
  
positive.code:  
   (defmethod allocate-space ((box xbox-pane) width height)
     (declare (ignore minor))
     (with-slots (contents) box
       (multiple-value-bind (majors minors) (allocate-space-aux box width height)
         ;; now actually layout the children
         (let ((x 0))
  
negative.code: 
  (defmacro dada ((&rest substs) &body body)
    "This is an evil macro."
    (setf substs (sort substs #'> :key (lambda (s) (length (symbol-name (first s))))))
    `(progn
       ,@(loop for k from 1 below (length (first substs)) collect
               (labels ((subst-one (new old sym)
  