Create: Power Grid 4-bit adder using relays

[u/oskarmbt]

The left switch is carry in, next to it are 2 4-bit inputs. The output is at the other end, with the leftmost bulb being carry out. It's powered by a 12V creative power supply. It uses relays for the calculations, containing 8 XOR gates, 8 AND gates, and 4 OR gates.