Why: In 1Q84:
But utopias don't exist, of course, anywhere in the world. Like alchemy or perpetual motion.Answer: Here are some, but I don't know about them. Some say "perpetuum motion," but let's not quibble.
"water driven wheel which when rotating drives a spiral hose water pump which lifts water to a header tank which feeds the water back to the wheel." What happens when the water evaporates?
A steel ball (about 2.7-in. diameter, 20 lb.) is rolling on an aluminum track, about 25 inches in diameter, placed horizontally. Three pendulums, about 45 inches long with tunable weights at the lower end, controls three horse-shoe magnets that the steel ball has to pass by on the track. Embedded in the track is a (mechanical) controlling/timing mechanism. It looks like a steel wire bent into a triangular track, 5 inches long. The ball rolls over it and pushes the wire down through a slot in the track. This affects one of the pendulums and regulates its swinging motion. The steel ball has not stopped revolving for months. We'll check back in 400 years.
There are lots of others. I don't think any of them work.
The More You Know: This one, "Freedom," was designed by Leonardo da Vinci 500 years ago, but in all that time, nobody has ever actually built one that has worked. I'm still holding my breath.
I don't know why all those clips are there.