Great stuff

It's similar to what I have so far with AND. AND is pretty much two transistors/relays connected in series. But I have a bit of a different approach because I want to avoid storing anything in memory as well as "loops", so everything has to be connected.

As for negative numbers, I would imagine the approach to be what's called "modular addition". This way you could add negatives and positives and all will be left is how you represent them. I'll dome some thinking about this because I really think I can make some type of calculator, and maybe have some QBasic happening too. Thanks for the program.