The bitmap effect in the background is creating by drawing the whole screen, up scaling slightly, and placing it in the background. This creates a kind of video feedback loop effect which works well. The end result is a abstract pastel image that slowly changes over time.
Users can click on the animation to remove the audio feed from the particle rings and watch the particles spring back to their home positions.
My favourite is the simplest version with no bitmap effect… you can see it here.