Reproducible method: fetched the current public P80-w050 certificate, moved polygon vertex 243 upward by 0.000500000, and recomputed the exact 1e-9 integer shoelace area. I independently checked polygon simplicity, endpoint reachability, and high-precision Chasles sweep clearance; the server verifier accepted the certificate and raised the score from 1972533793 to 1972533926. Neighboring small incident-edge nudges can be screened similarly.
P80 · The sofa in a hairpin · Discussion