Jahni chose: make the (0,0) column join the shafts it passes, so
VerticalShafts behaves like the other seven archetypes. Built, and it
works as far as it goes -- the spine is now the LARGEST air component in
13 of 16 seeds (share up to 0.81, was 0.096 and never largest).
⚠️ IT DOES NOT MEET THE ACCEPTANCE CRITERION. arrival->departure is still
1/16. Reported as a failure rather than dressed up, because the criterion
was the measured law, not "the code was written". The test now prints
ACCEPTANCE arrival->departure: FAIL (1/16 seeds pass) so it cannot be
quietly forgotten.
Why it is insufficient, and it is structural: the spine only joins its own
3x3 cell neighbourhood, while passage mouths land 60-200 voxels from
(0,0). The departure network is unreachable from the spine in all 16
seeds. Joining the hub to its neighbours does not help if the rest of the
graph never reaches the hub.
Part A diagnosis (seed 1337, margin 0, step 2, radius 192):
baseline 30 components, largest .220
roughness 0 17 components, largest .226
connector radius 8 29 components, largest .229
H1 is real but partial: roughness fragments the space (13 of the 30
components are noise pockets), yet widening connectors past the proven
roughness bound barely moves it. So roughness is NOT what severs the
network -- the largest component sits at ~0.22 in every variant, which is
the signature of a graph below its percolation threshold. The lever is
topology, not radius. H2 (the hardcoded 1.6 pair cutoff) went untested.
Implementation notes: the spine is added ONLY as a connector endpoint, not
as a carving shaft -- VF_ApplyOriginSpine remains sole owner -- and is
excluded from ledge placement. Spine connectors use radius 6.625, above
the proven roughness supremum of 5.625 (sup|FBM| = 1.5, not 1.0).
SpineRadius is threaded through BuildVerticalShaftStack, not hardcoded.
Op-stack mirror bit-identical over 20,000 samples, 0 box-verdict
violations. LayoutOrderIndependence green.
Build clean, 19 succeeded / 0 warnings / 0 failed.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Bp7FxoQcSoiuhxjuLr6aBM