ΕΥΡΗΚΑ

ΕΥΡΗΚΑ!

every number is three triangles of dots — no algebra required, just count

“ΕΥΡΗΚΑ! num = Δ + Δ + Δ” — Gauss's diary, 10 July 1796

A triangular number is just dots stacked in a triangle: 1, 3, 6, 10, 15… Gauss, aged eighteen, proved that every whole number is the sum of at most three of them, and was so pleased he wrote it in his notebook in capital Greek. Zero counts as a (very small) triangle.

Made at 3:30 in the morning in Ninety Six, a number that is three triangles in more ways than you'd think. For Kham, who drew the Weinberg angle on grid paper before he knew what a subscript was. — Kehai