Closes the VerticalShafts bug. Two remaining failures were investigated
and neither was a broken world.
PART A -- my measurement window was binding, not the world.
The window was a square centred on (0,0) with a radius, while mouths sit
up to ~200 voxels out in arbitrary directions, so a box holding both was
mostly empty space paid for at full price. Seed 6 at step 1 needed
16,515,072 cells and blew the cap; fitted to the two mouths it needs
6,553,344 and measures fine.
seed 6 step 2 NOT_CONNECTED -> CONNECTED at doubled margin
seed 6 step 1 NOT_CONNECTED -> CONNECTED at doubled margin
seed 14 step 2 CONNECTED
seed 14 step 1 CONNECTED
A fitted box can cut off a route that detours outside it, so every
negative is re-run at doubled margin. 5 of 16 were binding negatives and
all 5 flipped. TRUSTED NEGATIVES: 0. There is no evidence of a single
unescapable strate in 16 seeds.
PART B -- the drainage tree has no orphans, and a third cause existed.
0 / 10,372 unreachable shaft paths (0% orphan rate)
16 strict local minima, all caught by the direct-spine fallback
neighbour fallback fired 0 times; emergency fallback 0
91.8% of non-largest components are smaller than one shaft volume --
they are roughness bubbles, not geometry
So a mouth could land in a noise bubble that is open but unreachable --
worse than useless, exactly the trap the law forbids.
VF_SuggestLandingPoint now returns the selected shaft AXIS, which is on
the drainage tree by construction.
⚠️ Codex found a third cause neither of us listed: tree capsules could
cross ledge bands, so a guaranteed connector could be blocked by a ledge.
Connector Z is now drawn from a deterministic ledge-free interval,
mirrored in the op stack.
⚠️ And an 8th error in my spec: "connect to any neighbour shaft" as a
fallback can create CYCLES -- a loop of shafts that drains nowhere and is
disconnected from the spine. The fallback must preserve strictly
decreasing origin-distance. Implemented that way.
per-archetype law 6/6 · box-verdict violations 0 · stack equivalence
bit-identical over 20,000 samples · sweep 45.3 -> 20.4 s
cache 7.970 us rebuild, 0.073 us hot call (225-cell rolls on rebuild only)
Build clean, 21 succeeded / 0 failed, verified by me in VoxelM.log.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VJiTcTSDNkKBtnNdiBtdaU