But everything that happens in a processor is the result of simple logical operations: ANDs, ORs, NOTs, XORs and memory, all connected in different ways. And there’s some redundancy in that list: some of those logic gates can be constructed out of the others. The whole point of computers is you can perform billions of simple operations in a second, and complex operations are made out of lots of simple ones. When you’re working with binary numbers, all you need are simple operations.

Because of this, computers can actually be built out of physical parts, without even electricty, they’ll just be much bigger, and slower, and less durable, and may need some motor attached to them. Mechanical calculators have existed since the 1700s, and in the 50s-70s were common sights in offices. Arguably the first general-purpose computers, Charles Babbage’s Difference Engines (Wikipedia), were made from mechanical parts, but they had the disadvantage of not being made out of colorful pieces of plastic.

Shadowman39, an artiste who works in the medium of K’nex, has made a number of devices out of those construction toys, but an ALU, an Arithmetic Logic Unit that can increment, add, AND and XOR two binary numbers, is probably his most “practical” creation. He shows it off in this 15 minute Youtube video:

This ALU is one part of a larger processor project that’s still being built. I hesitate to call it a “microprocessor,” maybe we should call it a macroprocessor. We wish Shadowman39 the best, and hope he has enough time, energy and parts to realize his wondrous, ludicrous dream.

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