The author of this amazing piece describes it as a “Handdrawn audioresponsive video exploration”, but if you read the comments section where he posted it to Vimeo, he’s a little more clear about the handdrawn-ness of it . When I first read the description and saw the animation, my jaw-dropped because I imagined this guy using all sorts of cutout shapes and rulers to create it. Well thats not exactly the case. But its still pretty cool because he used Actionscript 3, recorded where his mouse went in realtime, and it sounds like a different audio file would have produced a slightly different animation.
I did teach a tutorial on stuff like this a while back using both Actionscript 3 and 2. It involves Flash’s Drawing API (hey look, there’s that misleading word “draw” again)