anchor.diff:  
   (defun e ()
      (load 'fa.lisp)
  +   ;(edge "images/odetojoy.png" "output/odetojoy_edge.png")
      (edge "images/the_scream.png" "output/scream_edge.png")
      ;(edge "images/starry_night.png" "output/starry_night_edge.png")
      )
  
positive.code:                (loop for i below height do
                    (loop for j below width do
                       (setf c 0)
                       (setf w 0)
                       (setf l 0)
                       (setf v 255)
                       (setf empty nil)
                       (dolist (f (multiple-value-list-remove-nulls (8-neighbors img i j)))
  
negative.code:    (format t "Edge thinning (long process)~%")
     (edge-thin img)
  
     (format t "labelling ~%")
     (setf img (colourise-components img))
     ;(format t "K-means clustering~%")
     ;(format t "~S~%" (k-means-cluster-image-pixels img 2))
  
     (format t "Writing to file~%")
     (write-image img output)) ; output the image for now
  
  