The interesting aspect of many patterns is their dynamic behavior. We can certainly show this with interaction diagrams, but only in the context of a specific model; it is harder to keep the "patternness" of the patterns open. Finally patterns are templates, in a sense, in which classes, associations, attributes and operations might all be mapped into different names which [I wonder if this should be "while"?] keeping the essence of the pattern; we need a way to clearly parameterize the patterns. Nevertheless we feel that we have enough facilities to capture patterns within the UML by expressing them in terms of interactions.”