In 1936, a 26-year-old German engineer named Konrad Zuse quit his stable job at an aircraft factory, moved back into his parents' living room in Berlin, and started building a computer out of sheet metal. Not relays. Not vacuum tubes. Just thin metal plates cut with a jigsaw, stacked and pinned together into thousands of sliding parts that could add, subtract, and store numbers in floating-point binary — an architecture so modern it wouldn't become standard until the 1980s IEEE 754 spec.

The Z1 is arguably the world's first programmable binary computer, and it was entirely mechanical. Zuse designed his own logic gates using overlapping metal slots. When one plate moved, it either allowed or blocked another plate from sliding — a physical implementation of Boolean AND and OR. He then wired roughly 20,000 of these parts into a working 22-bit floating-point processor with a 64-word memory, driven by an electric motor turning at 1 Hz. Programs were fed in on punched 35mm movie film, because celluloid was cheap and Zuse couldn't afford proper punch tape.

Here's where it connects to things you already know. While Alan Turing was publishing his abstract paper on computability in 1936 and Claude Shannon was about to link Boolean algebra to circuits in 1937, Zuse — working in near-total isolation, unaware of either — was independently building the physical embodiment of those ideas. He arrived at:

• Binary arithmetic (Leibniz had described it 250 years earlier, but nobody used it for computing)
• Floating-point numbers with a separate exponent and mantissa
• Separation of memory, control unit, and arithmetic unit — essentially the von Neumann architecture, a decade before von Neumann's report
• A microprogram stored on tape, distinct from the data

The catch: the Z1 was mechanically unreliable. The metal plates jammed constantly under the friction of so many synchronized parts. It rarely completed a full calculation without seizing up. Zuse iterated — the Z2 replaced the arithmetic unit with telephone relays; the Z3 in 1941 was fully relay-based and actually worked, making it the first working programmable computer in history.

And then Allied bombers destroyed the Z1, the Z2, and the Z3 in 1943–1944. Every original was lost. The blueprints survived only because Zuse himself had escaped Berlin with them in a suitcase.

The story doesn't end there. In 1986, at age 76, Zuse decided to rebuild the Z1 from memory and his old drawings — a project that took him three years and was funded partly by Siemens. That reconstruction sits today in the German Museum of Technology in Berlin. It still jams.