Javascript

two chess projects live in this codebase, and honesty requires separating them up front. the first is a from-scratch javascript engine (in arcade/references/chess/js/, built following the classic bluefever software series): 120-square mailbox board, hand-rolled move generator validated by perft, material + piece-square evaluation, alpha-beta with quiescence, a principal-variation hash table, and iterative deepening. the second is voice chess (code/private/chess-bot/, published as github.com/abaj8494/ollama-voice-chess): there i did not write the engine — stockfish plays the moves over uci — and the engineering is in the wrapper: skill throttling, an ollama llm that provides spoken commentary without being allowed to hallucinate moves, neural tts, and spaced-repetition opening training. one project teaches you how engines work; the other teaches you what to build around an engine. 𐃏

sudoku is the drosophila of constraint satisfaction: small enough to hold in your head, rich enough to demonstrate every solving paradigm that matters. this page works through four of them against my actual code — a backtracking solver with \(O(1)\) constraint sets (arcade/references/sudoku/solver.py), a dart port that also generates puzzles (arcade-mobile), an integer-programming formulation solved for real with scipy, and the exact-cover view that leads to knuth’s algorithm x. every timing below is a real run on this machine.