The FCC substrate — our flavor

moore26 runs on the 26-neighbor Moore grid, but its transport layer is deliberately not cubic: only 12 of the 26 channels carry packets — the face-diagonal FCC edges — and only on the even-parity sublattice. The result is a local causal unit that is geometrically a rhombic dodecahedron, not a cube.

Channel layout

Registers	Channels	Role
faces	0–5	structure only (no transport)
edges	6–17	the 12 FCC transport channels
corners	18–25	structure only

The 12 transporting directions are the FCC edge vectors — every {±1,±1,0}, {±1,0,±1}, {0,±1,±1} combination:

(1,1,0) (-1,-1,0) (1,-1,0) (-1,1,0)
(1,0,1) (-1,0,-1) (1,0,-1) (-1,0,1)
(0,1,1) (0,-1,-1) (0,1,-1) (0,-1,1)

All 12 have length √2; adjacent directions have dot product 1 (cos 60° = 1/2 — the bend-handoff projection weight).

The parity lock

Transport runs only on even-parity cells ((x+y+z) & 1 == 0). Edge hops preserve parity: a (1,1,0) hop sums to +2, so even cells map to even cells. The odd sublattice is dead space for packets — the vacuum's transport graph is the FCC even-sublattice, not the full cubic grid. Packets arm only on even cells; odd cells still hold winding and structure.

The geometry

• Voronoi cell: the FCC lattice's Wigner-Seitz cell is the rhombic dodecahedron — 12 rhombic faces, each facing one nearest neighbor = one transport channel. Face-transitive: every channel is symmetry-equivalent (which is why transport is isotropic — the fairness is geometric, not a rule).
• The register map IS the polyhedron: 12 faces + 6 axis vertices + 8 corner vertices = 26 channels. The 6 order-4 vertices (axis positions (±2,0,0)) are the face channels ch0–5; the 8 order-3 vertices (cube corners (±1,±1,±1)) are the corner channels ch18–25; the 12 rhombic faces are the transport edges ch6–17. Vertex order explains the asymmetry: 4 transport faces meet at each axis vertex vs 3 at each corner — ⟨100⟩ axes are structurally more congested than ⟨111⟩.
• Neighbor shell: the 12 nearest neighbors sit at the vertices of a cuboctahedron (the rhombic dodecahedron's dual — an Archimedean solid).
• Symmetry: full octahedral Oh (*432, order 48). The distinguished axes are ⟨100⟩ and ⟨111⟩ — the same easy axes real cubic magnets pick.
• {111} planes: cross-sections perpendicular to body diagonals are perfect hexagons — the 6-edge ring where two counter-rotating slipstreams coexist (the geometric Pauli pair) and a third is refused.
• Hexagon hop sequence: ch8,12,16,9,13,15 — the six edges ⊥(1,1,1), each a 60° turn.

Why not cubes?

The plain Moore-26 grid would let packets move on axis (±1,0,0) edges and corners (±1,±1,±1) — unequal hop lengths, anisotropic timing, and the parity check fails. Restricting transport to the 12 √2 edges on one parity sublattice gives a graph where every hop is identical: same length, same tick, same cost. v = 1 hop/tick is isotropic by construction, measured 1.00 on all 12 axes with zero dispersion over nu = 1–255.

The cubic grid is still there underneath — faces and corners hold structure (winding registers live on all 26 channels) — but the causal traffic runs on the FCC skeleton inside it.

Registers per node (392B)

winding[26], packet[26], packetNu[26], packetBorn[26], mass, massFlight[26], charge, chargeFlight[26], incip, incipNu, incipBorn, phase (0–511, currently vestigial — phase_sync kill-switch verified phantom), heat, ack, bondDist, localDensity.

The winding pair split (2e/2e+1) carries direction as dd = a − b imbalance — stored angular momentum, sticky and structural. Slipstreams are dd on a channel; the {111} hexagon hosts exactly two (CW + CCW) = the Pauli pair.