Writing

Essays

Things I have learned. Things I built, broke, and eventually figured out.

How to solve the 2D rectangle variant of the IQ fit puzzle: math and code Jul 26, 2026 · 17 min Twelve ball-pieces, an 11×5 board of fifty-five holes, and one exact covering. Symmetry cuts the search space for free via the dihedral group, a counting argument proves that a full board is a solved board, and a Rust solver packs the whole grid into a single u64 so every placement is a bitwise AND. algorithm · group-theory · math