Lightyard
About fifteen years ago a puzzle game called Trainyard came out for iOS and took my dev team by storm for a few weeks. It ceased getting updates some years ago and isn't on the app store anymore. So I came up with a variant on it and just put up https://www.geoffcanyon.com/lightyard.html I need more puzzles to include in the base pack, if you come up with something interesting, export it and send it to me!