OK, you have to admit, that’s pretty cool. If Sir Isaac Newton was an organ grinder, this would be the machine he cranked. It’s interesting to watch, and it makes a jolly little noise as it works. It’s plain neato.
But being cool is only half its appeal, especially to the builder. You see, it’s only necessary to build this machine once. It doesn’t do anything, so there’s no way it can break down. If it fails to do the nothing it was designed to do, you can safely ignore it. It’s not a life support device or anything. You wouldn’t have to fix it, or build another one if it broke. The marbles go round and round and make noise. If they don’t go round and round and make noise, the machine would make pretty fair kindling. It’s a win-win device.