Hammers and wheels
a spinnable model of the three reels, the code disc behind each, and the finger comb over each disc
Pick symbols or leave them on random, then pull. Each reel stops on the timing measured in VID-01, the fingers drop, and a lever falls only when every finger it needs has found a hole. Below it, the slides: which set travels, and how many quarters that is (§3.5, §3.6). Schematic, not a scan; the real castings look different, the logic is the same.
The model is also a page of its own: models/hammers-and-wheels.html. MILLS-family schematic.