The 4004 is so weird that it stands in a class of its own, for me. I'm not sure how much of its instruction set came from Busicom, the company that the 4004 was

The 4004 is so weird that it stands in a class of its own, for me. I'm not sure how much of its instruction set came from Busicom, the company that the 4004 was made for, instead of from Intel engineers.