anchor.diff:  	 (method-name
   	   (concatenate 'string
   			(symbol-name concept-symbol)
  -			"-IMPLEMENTATON-TAG-SETTER"))
  +			"-IMPLEMENTATION-TAG-SETTER"))
   	 (method-symbol (find-symbol method-name *concepts-package*))
   	 (method (if (and method-symbol (fboundp method-symbol))
   		     (symbol-function method-symbol)
  
positive.code:   (let* ((method-name
  	  (concatenate 'string
  		       (symbol-name concept-symbol)
  		       "-IMPLEMENTATON-TAG"))
  	 (method-symbol (find-symbol method-name *concepts-package*))
  	 (method (if (and method-symbol (fboundp method-symbol))
  		     (symbol-function method-symbol)
  		     nil)))
      (unless method
        (error "Cannot find concept-specific implementation tag method for concept  ~A.  Symbol named ~S either not found or not fboundp!"
  	     concept-symbol
  	     method-name))
      (apply method concept-args)))
  
  
  
negative.code: 	(setf (symbol-value concept-symbol)
  	      implementation-tag-symbol))
        `(progn
  	 (let ((*package* ,*concepts-package*))
  	   (defmethod ,concept-implementation-tag ( ,@(jp.doc-ll:documented-lambda-list->lambda-list documented-lambda-list) )
  	     (let ((concept-symbol
  		     (find-symbol 
  		      (symbol-name 
  		       (%create-concept-symbol
  			',concept-name
  			',(jp.doc-ll:documented-lambda-list-argument-types documented-lambda-list)))
  		      *concepts-package*)))
  	       (if (and concept-symbol
  			(boundp concept-symbol)
  			(not (eq (symbol-value concept-symbol) +UNSET-IMPLEMENTATION-TAG+)))
  		   (values (symbol-value concept-symbol)
  			   concept-symbol
  			   (eq (symbol-value concept-symbol) +UNSET-IMPLEMENTATION-TAG+))
  		   (if (next-method-p)
  		       (call-next-method)
  		       (values (format nil "** ~A" ,concept-symbol)
  			       ,concept-symbol)))))
  	   (defmethod ,concept-implementation-tag-setter  ( new-tag ,@(jp.doc-ll:documented-lambda-list->lambda-list documented-lambda-list) )
  	     (let ((concept-symbol
  		     (find-symbol 
  		      (symbol-name 
  		       (%create-concept-symbol ',concept-name
  					       ',(jp.doc-ll:documented-lambda-list-argument-types documented-lambda-list)))
  		      *concepts-package*)))
  	       (setf (symbol-value concept-symbol) new-tag)))
  	   (define-concept-method-impl ,method-name (,concept-check ,@normal-lambda-args) ,@body))))))
    
    
  ;;;;
  ;;;; Some test concept implementations
  (implement-concept 
  