Here’s a new interactive demo.
It’s using TimelineMax for the animation and Adobe Edge’s bindSymbolActionfor the newly added balls to create an echo effect of the main ball. You can have them as multi-coloured or plain grey. You can also change the frequency of the echoes.
Don’t forget that once you have clicked ‘Play’ button you can then click the ‘Mouse’ button to drag your mouse back and forth to scrub through the animation by hand (which I think is pretty cool ‘though I say so myself!).
Change the values, scrub around and have a play!