@kenshirriff this reminded me of an old Zachtronics Flash game, "KOHCTPYKTOP: ENGINEER OF THE PEOPLE," which was all about putting together CMOS logic on a layered grid of pixels. I never made it very far in.
Game website zachtronics.com/kohctpyktop-en
Tutorial video for those who want to see it without trying to get Flash working youtube.com/watch?v=-7Wf7h5QlU