Mechanical simulations are still used from time to time. One prominent example is a mechanical simulation of the San Francisco Bay and its environs, erected in a giant warehouse taking up more than an acre just outside San Francisco. It’s a scale model, with enormous amounts of water moved by hydraulic mechanisms to simulate tides, currents, and other forces. It was built to test whether a plan for building dams on the bay would work. The mechanical simulation showed that it wouldn’t, and the dams were never built.
