A useless machine is a device which has a function but no direct purpose; it may be intended to make a philosophical point, as an amusing engineering ‘hack’, or as an intellectual joke. Devices which have no function, or which malfunction, are not considered to be ‘useless machines’.(wikipedia)
The pendulum was created by YouTuber Mike Rouleau, and the mechanics and engineering are truly impressive.
Dual Axis Reaction Wheel
It’s a fun bit of engineering, but are there any practical uses for this crazy creation?