FixedPatchSet2D.fine_layout rejects non-positive, float, bool or wrong-length block sizes with ValueError before any modulo (was ZeroDivisionError/TypeError). The face gap-4 GPU test now checks raw owner cores directly by kind/covered for every patch (ACTIVE finite, OUTER/holes/covered NaN; INNER not asserted), not only the masked download and reversed-order parity. README documents the body-free multipatch call, scope and level-wide fine shape. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>