you’d think there wouldn’t be much new ground to explore in the field of power transmission. And then you see something like an infinitely variable transmission built from nested pulleys, and ...

Pulleys are found in lifts ... part with teeth that interlock with another gear or belt to transfer motion and power while changing speed, or direction in a mechanical system.

“Crossbow made with pulleys and power springs. The complex mechanism, which required advanced mathematical and mechanical understanding to craft, was likely made by a certain genius who learned ...