This is a video of engineer and Youtuber Daniel de Bruin constructing a tiny marble machine from scratch that's only big enough for a little ball bearing to ride. Obviously, this is the perfect unit to own in the event a marble machine loving friend of yours goes to prison, because you could easily sneak this into them in that ass of yours. "Excuse me?" Here, why don't you take this Newton's Cradle too?
Keep going for the full video.
Thanks to Jan, who agrees it's not the size of your marble maze that matters, but how your balls flow.