1. Computers don’t have to be electronic (Archimedes’ Antikythera Mechanism, a way to chart the position of the planets dating back to the ancient Greeks; here’s a video telling what it is and showing a working model [7 minutes])
2. Computers don’t have to be electronic (Charles Babbage and Ada Lovelace’s Difference Engines; here’s a video about it [5½ minutes], with some clips of one in operation)
3. Computers don’t have to be electronic (The Digi-Comp 1 kit from 1963, computing with rubber bands; here’s a video about it, 16 minutes)
4. Computers don’t have to be electronic (Turing Tumble, a kit and game you can get that does computations with the action of falling marbles; here’s their Getting Started video [5 minutes])
5. Computers don’t have to be electronic (The 8-Bit computer built of K’NEX parts called the MechaDigit-1, bits posted here twice before; here’s video of it [18 minutes]; and here’s an older project called the K’nuter [10 minutes])
