I had an interesting dream last night. I was at a science museum with various family members. One of the items we saw was a windmill that didn’t really rely on wind.
Its blades were made up of multiple weights on tracks that slipped around as it turned so that the balance was off just enough to make it keep turning. Kind of like the “Wonder Wheel” on Coney Island in terms of the weights tracks, though it keeps itself moving because of gravity.
I’m not much of an engineer, so if anyone wants to play with this idea, have fun, but let me know how it goes!