anchor.diff:  
   (defun subdivide-rect (rect placed)
     (if (intersectsp placed rect)
  -      (with-rect (x y w h) rect
  -        (with-rect (xp yp wp hp) placed
  +      (%with-rect (x y w h) rect
  +        (%with-rect (xp yp wp hp) placed
             (let (result)
               ;; left part
               (when (splitsp xp x (+ x w))
  
positive.code:      finally (return (delete-if #'null result))))
  
  (defun subrect (w h rect)
    (with-rect (x y) rect
      (list x y w h)))
  
  (defun place-rect (w h free-rects)
  
negative.code:              :scale 32
               :spread 0.1))
  
  #++
  (time
   (make-atlas "/tmp/atlas.png" "/tmp/font2.met"
               "/Library/Fonts/Arial.ttf" 48
               :scale 32
               :spread 0.1
               :width 300
               :height 300))
  