Mechanical Watch Simulation
Fully working, interactive 3d mechanical watch model and explanation.
Mechanical Watch by Bartosz Ciechanowski. An absolute masterpiece of simulation, modeling, explanation, and teaching. If you've ever wanted to learn the full details of how a mechanical watch functions, this page will teach you with an incredibly detailed breakdown of a normal mechanical watch, but simulated in fully-interactive 3d models, to go along with the English explanations.
If you're interested in going deeper, the Javascript driving the simulations is about 8500 lines of unminified code, though you'll have to use your browser to inspect the watch.js file.