I made an 8-bit computer that can be programmed using low level "assembly" chips that can be easily swapped out. Yes, I know its ugly and the design is totally incorrect, but it works, and I didn't have any experience designing anything like this before watching Sebastian's videos. It can be programmed to add, multiply, subtract values and store them into the RAM by simply swapping out the chips on the program side. (left side). It can also be hooked up to the clock piece to automatically finish its given instruction set, and halt when finished.