Conclusion

At this point, we've looked at every single line of code that you have and visited and re-visited some important concepts that make this animation work. Animating many elements does require some extra work as you've seen. The bulk of our code, now that you've seen all of it, is in re-creating our retained mode graph that maps between all of the circles in memory to what actually gets shown on screen. Once you master that little detail, creating any kind of animation that involves many elements will become a breeze.