Real Artificial Improvisers

Most artificial improvisational agents are restrained by their creator's naive definition of improvisation. If improvisation is understood as a choice amongst possibilities rather than simply the act of creating, it's obvious why: the choice of most agents is not their own, but their creator's. The agents simply carry out the creation. A true improvisational agent would be able to develop its own preferences. The closest thing I've seen to this yet is the Bacterial Orchestra.