Yes, a bitcoiner friend's kid described to me step-by-step how to build a CPU from scratch. Complete with a program counter, 8 bit memory, addition, subtraction, multiplication and several other essential operations all starting from discrete logic gates - not even flip-flops were taken for granted. From my EE101 experience, it seemed to check out but honestly I could only barely keep up with his pace. I think he's 12. Oh, and there was no pencil or paper involved, just from his memory of previously trying to build one in simulation.