I'm still very much a believer in the spontaneity of certain kinds of writing. But then you have to eventually, when you're writing a long play, make adjustments along the way - all kinds of adjustments.
I'm a great believer in chaos. I don't believe that you start with a formula and then you fulfill the formula. Chaos is a much better instigator, because we live in chaos - we don't live in a rigorous form.