anchor.diff:        list))
         
   ;;; p09
  +
   (defun pack (list)
     "Pack consecutive duplicates of list elements into sublists.
   If a list contains repeated elements they should be placed in separate sublists.
  
positive.code: ;;;; Compression, packing, etc.
                        
  ;;; p08
  (defun compress (list)
    "Eliminate consecutive duplicates of list elements.
  If a list contains repeated elements they should be replaced with a single copy of the element. 
  
negative.code:           (encode list))) ;p11
            
  ;;; p12
  
  (defun decode (list)
    "Decode a run-length encoded list.
  Given a run-length code list generated as specified in problem P11. Construct its uncompressed version."
  