anchor.diff:  	(setf (symbol-value concept-symbol)
   	      implementation-tag-symbol))
         `(progn
  -	   
  +	 (defmethod ,concept-implementation-tag ( ,@(%documented-lambda-list-to-lambda-list documented-lambda-list) )
  +	   (let ((concept-symbol
  +		  (find-symbol 
  +		   (symbol-name 
  +		    (%create-concept-symbol
  +		     ',concept-name
  +		     ',(%documented-lambda-list-argument-types documented-lambda-list)))
  +		   *concepts-package*)))
  +	     (if (and concept-symbol (boundp concept-symbol))
  +		 (values (symbol-value concept-symbol)
  +			 concept-symbol)
  +		 (if (next-method-p)
  +		     (call-next-method)
  +		     (values (format nil "** ~A" ,concept-symbol)
  +			     ,concept-symbol)))))
   	 (define-concept-method-impl ,method-name (,concept-check ,@normal-lambda-args) ,@body)))))
   
   
  
positive.code:   (let ((method-name (intern (concatenate 'string (symbol-name concept-name) "-IMPL")))
  	(normal-lambda-args (%documented-lambda-list-to-lambda-list documented-lambda-list :error-on-missing-doc nil))
  	(concept-symbol (%create-concept-symbol concept-name 
  						(%documented-lambda-list-argument-types documented-lambda-list :error-on-missing-doc nil))))
      (let* ((implementation-tag-+ (concatenate 'string "+" (symbol-name implementation-tag) "+"))
  	   (implementation-tag-symbol 
  	    (find-or-make-implementation-tag implementation-tag-+ (symbol-name concept-name) doc))
  
negative.code: ;;;; Creates a symbol based on a concept and the typed arguments given 
  ;;;; to it
  (defun %create-concept-symbol (concept-name arg-types &optional (package *concepts-package*) )
    (multiple-value-bind (s present-already) 
        (intern (apply #'concatenate 
  		     'string 
  		     (symbol-name concept-name)
  		     (if (every #'(lambda (type) (eq type 't)) arg-types)
  			 nil
  			 (mapcar #'(lambda (type)
  				     (concatenate 'string
  						  "["
  						  (format nil "~S" type)
  						  "]"))
  				 arg-types)))
  	      package)
      (when (not present-already)
        (setf (symbol-value s) +UNSET-IMPLEMENTATION-TAG+))
      s))
  		       
  		       
  