ChessFly

Play chess against the complete connectome of an adult fruit fly. The FlyWire brain (138,639 neurons, 15.1M connections) runs in your browser on WebGPU: the board drives its 10,855 visual sensory neurons, activity settles over 5 steps across the whole graph, and the central brain and descending neurons are read out into a move and a win probability. Every forward pass lights up the 3D brain as it happens. The brain and the weights are about 150 MB, downloaded once and then cached.

The wiring is fixed, exactly as the reconstruction has it, signs included. Only the encoder, the strength of each connection, each neuron's homeostatic gain and threshold, and the readout were trained, on Stockfish-annotated Lichess positions. A depth-3 search runs on top, where a whole tree level is one batched forward pass through the brain.

Weights: mlabonne/chessfly. Source: the repository's web/ directory. GPL-3.0 due to chessground. The leg that moves the pieces is a real housefly foreleg: High Resolution Photo of a Housefly (Musca domestica) Leg by GorissM, CC BY-SA 2.0, via Wikimedia Commons, cut out, colour-balanced and split at the joints (src/assets/leg/).