anchor.diff:                        shift-width)
     (dolist (window (funcall collect-windows-fn window-list))
       (cond ((/= 0 shift-width)
  -           (window-move window 0 shift-width))
  +           (window-move window shift-width 0))
             ((/= 0 shift-height)
  -           (window-move window shift-height 0)))
  +           (window-move window 0 shift-height)))
       (cond ((/= 0 diff-width)
              (window-resize window 0 diff-width))
             ((/= 0 diff-height)
  
positive.code:              (window-resize window (- diff-height) 0))))
      (cond ((/= 0 shift-width)
             (dolist (window shrink-window-list)
               (window-move window 0 shift-width)))
            ((/= 0 shift-height)
             (dolist (window shrink-window-list)
               (window-move window shift-height 0)))))
    t)
  
  (defun shrink-top-windows (window-list n)
  
negative.code:                    width
                     height))
  
  (defun window-move (window dx dy)
    (window-set-pos window
                    (+ (window-x window) dx)
                    (+ (window-y window) dy)))
  