List,

when it comes to software components / composition / extensibility,
everybody seems to bang her/his keyboard against the same paramount
monolith (see [1] for an illustrative example):

   extend state or extend behavior or both

Isn't there something else? Is this the end (in the sense of: tail) of the
story? No sequel in sight, nothing *new* ?

/Klaus

[1] http://citeseer.ist.psu.edu/zenger02extensibility.html