anchor.diff:  ;;;   http://en.wikipedia.org/wiki/Trie
   ;;;
   
  -(in-package #:twist)
  -
  -(setq *print-pretty* t)
  +(in-package #:prodigy-logic)
  +
  +;(setq *print-pretty* t)
   (setq *print-circle* t)
   (setq *print-level* 12)
   
  +#+sbcl
  +(defparameter +word-marker+ #\t) ; SBCL + swank causes problems with UTF-8
   #-sbcl
  -(defparameter +word-marker+ #\+) ; SBCL + swank causes problems with UTF-8
  -#+sbcl
   (defparameter +word-marker+ #\u2022) ; • Bullet
   
   (defparameter *debug* nil)
  
positive.code:     (add-seqs r (mapcar #'(lambda (s) (string-downcase (string s))) lst))
      r))
  
  
  ;;; Predicates
  
  (defun leafp (node)
    "Predicate to tell if there are no branches for a node."
    (equal nil (trie-branches node)))
  
  (defun wordp (node)
    "Predicate to tell whether this node ends any words."
  
negative.code:     (write-char #\Space)
      
      ; Print width
      (write (width trie))
      
      ; Word ending
      (when (and compact (wordp trie))
  