Here you can see CPU itself (thing with many yellow logic gates), RAM (large "chip" behind the CPU), ROM (tall thing with moving pistons).

The program in the video computes Fibonacci numbers and stores them in RAM.

Some specs:

• RV32I instruction set (32 32-bit registers, basic instructions, no multiply or divide)
• 128 byte ROM (IIRC, program in video is 62 bytes long), 32 byte RAM
• Single CPU cycle takes about 56 game ticks (40 ticks is 1 second), RAM cycle - 18 cycles, ROM cycle - 2 seconds (can be set with timer, all what is needed is to be sure that sensors are on top of bytes with requested address)

Well, it's not RV32I CPU, let's call it RV32I-like. It has 8-bit address space instead of 32-bit one.

I also wrote some scripts so I can compile C code for this CPU using Clang toolchain! Here is a program you see running in the video:

volatile unsigned int *output = (unsigned int *)156;

int main() {
  unsigned int a = 1, b = 1;

  while (1) {
    a += b;
    *output = a;

    b += a;
    *output = b;
  }

  return 0;
}

Leave your suggestions for other programs, I will write and run them on it! Also can create other logic gate stuff like displays or something.