Not my project, but I wish it was. I've always wanted a pinball machine, but now I have modified that want, specifically to a 1970s mechanical pinball machine.
I absolutely loved these two videos, that explain the relay logic of mechanical pinball in detail.
I actually dabbled with relay logic myself once. In 1975, when I was in high school, I designed and built a "who's first" answer buzzer system. It was intended to be used for training the school's TV quiz show team. Unfortunately, it didn't work very well, as my design didn't compensate for momentum in the relay solenoid
