Check out this incredible machine someone built

Watch videos of it in action here:

https://www.youtube.com/watch?v=XVvhCLuZBic
https://www.youtube.com/watch?v=XhV_DOtsWck
https://www.youtube.com/watch?v=bqIGAN9P7u0

This incredible use of balls comes from reddit user 'little_angel_950'.