well, I've always been of the opinion that most ACM is done purely by instinct, in trying to save yourself and/or get your nose on to the opponent, you pull moves that may or may not have been done by others (A particular favorite mine is the hammerhead)
also, many maneuvers are invented purely on the spot to save your butt
(aka, the Mako spin, which involves all kinds of fancy stick moves to keep someone right behind you from getting a shot, usually called by dweebs stick-stirring)