Nice idea. I built a one part device.

Sadly it looks like there's a bug in Google's saving code, so there's an extra (completely unnecessary) wall.

https://developers.google.com/events/io/input-output/ahNzfmd...

If you're going to share your output, make sure that what you're sharing is what you saved!

Edit: And on top of that, it depends on your screen size. Hopefully the registration system doesn't have as many problems!

It also appears to have a random? element with regards to ball behaviour. Each run of this https://developers.google.com/events/io/input-output/ahNzfmd... ends up different. Sometimes it hits the wall, sometimes goes over it and sometimes it makes in into the output. (should be two items on your screen - resize until you see a Track and a Wall)

Seems difficult to design and share if ball behaviour changes run to run. Unless that is part of the point - simulating real world user input ;)