A bow tie's crossing edges change side along their length, so the side a
midpoint probe found let floor shadows cull both diagonals and leave the
lobe behind them lit. Edges something crosses or meets inside their
length are now unknown, which only costs a seam or a shadow face; along a
run of a ring that nothing else comes near the side cannot change, so one
probe answers for the run. Cone edges and floor shadows share the answer,
computed once per runtime wall at load instead of per edge on the first
floor frame (Lotus: about 20 ms against 360 ms in a debug test).

Runtime edges carried under a piece's heights may no longer also name
members, which the loader ignored.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>