NodeDiscs now circular, with randomized transparency and hue.  NodeDiscs now Tween toward brown/gray as they age and then animate like bubbles off the top of the stage.  When they are off they dispatch an event that they are gone and then remove themselves from their parent.  Use a medium gray for the Stage background.  Make the Stage wider and taller.  Make the TwigSections a little narrower.  Allow many more Twigs.  Now requires greensock TweenLite and plugin classes.