That is really neat. I love the motion. Are there any issues with jamming? I see that the rotating piece at the top of its rotation can trap balls. In the video it happened with two balls a couple of times and they just popped up. Does it always do that? Again, awesome.
You're right that balls sometimes get stuck. The rotating parts are a bit flexible, so the machine will continue running anyway. It survived its first exhibition without any problem, despite being flooded many times.