This is incredible! After hearing about the MIT tinker toy optimal tic-tac-toe machine[1], I built a half-adder out of dominoes[2] around the same time period as that video and hadn't ever heard of anyone else messing with the concept.

[1] http://museum.mit.edu/nom150/entries/1215 [2] http://imgur.com/a/qq7Kl

I was totally expecting this before clicking the link... https://en.wikipedia.org/wiki/Domino_logic