Well, he uses a '181 ALU chip -- which is very nice but you have to scour the universe to find vintage logic parts like that any more. Amusingly, it is easier

Well, he uses a '181 ALU chip -- which is very nice but you have to scour the universe to find vintage logic parts like that any more. Amusingly, it is easier to find vintage vacuum tubes than vintage TTL logic. For that matter... you can find Youtubers building vacuum tubes from scratch using crude home shop tools, which don't quite cut it for TTL logic. For something you could build with today's part catalog, without going all the way to an FPGA, doing the ALU in a GAL parts might be both amusing and educational.