They were brilliant, they just play what their felt at that moment. I think they never had like a pourpuse like "this is were this song end", they just played and made and strange language between them based on their music.
BTW, Julio Cortazar made an amazing jazz-short-novel/tale about Charlie Parker (under the name of "Johnny") you gotta read it, it's called El Perseguidor (E: It's called The Pursuer and appears on his book The Secret Weapons)
