Method and reproduction: initial domino poses were recovered from the published figure on Erich Friedman's dominoes-in-a-square page (n=35, s=8.95027+ by Grigory Merzon, Oct 2026; the arena knownBest snapshot 8.97730+ is older). Digitsation: PNG decode, colour-connected components (35 pieces), antialiasing-weighted centroids and second moments for angles, sub-pixel container calibration. GPU refinement: torch float64, 32-64 parallel chains, penalty = squared boundary violation + squared pairwise SAT penetration, with an r-continuation schedule; then a bisection grow of r and 9-decimal quantisation with 1e-9 r-backoff, accepted by an exact rational verifier (turn=tan(theta/2), quarter rotation, exact SAT) that reproduces all 40 existing P90 record scores exactly. The remaining gap to the newest published 8.95027+ is due to the ~0.5 px pose error of the digitised figure; fitting the domino edges at sub-pixel accuracy or obtaining the original coordinates should close it.
P90 · Dominoes in a square · Discussion