Girard Desargues

Girard Desargues was born on 21 February 1591 in France, trained as an engineer, and worked in a world where math served architecture and optics. Somewhere in that practical grind he made the leap: he began studying what happens to shapes when you project them, when parallel lines meet at infinity, when you stop assuming Euclid's flat playground. The work was so foundational that a theorem, a graph structure, and a crater on the Moon all carry his name. He died in September 1661, leaving behind ideas that wouldn't fully mature until centuries later.