diff --git a/docs/re/BACKLOG.md b/docs/re/BACKLOG.md
index c0253eb..eabeccc 100644
--- a/docs/re/BACKLOG.md
+++ b/docs/re/BACKLOG.md
@@ -355,11 +355,26 @@ search cannot find a *schedule*.
   (13 467/13 467 inside the bbox) and **section 2 is a plane list** — unit normal,
   signed distance, and a point, with `n·p + d = 0` to float round-off in
   **133 573/133 573**. Section 1 (96 B) still ❔ in meaning, though its slot
-  regions are censused. ❌ **The static coupling search is exhausted**: every
-  index-shaped field in the cell payload has been followed into all three
-  sections and checked for spatial agreement against controls — nothing above
-  chance. Settling it needs the PE code that reads `REGN`, not more correlation.
+  regions are censused. My static coupling search found nothing above chance —
+  every index-shaped field followed into every section, against controls — and
+  I concluded it needed the PE code rather than more correlation.
+  ✅✅ **SOLVED on branch `auto/regn-reader` (2026-08-26).** `REGN` is a
+  **tetrahedral navigation mesh**. The route in was the **`POF0` fixup table**:
+  it is the loader's own list of which words are pointers, so nothing had to be
+  guessed. There are **six** sections, and the chain is
+  `position → cell → 32-byte item → tet refs → tetrahedron`; section 2 is a
+  **face** carrying a plane plus its 3 vertices and the two tetrahedra either
+  side. Checked with controls: each face passes through exactly 3 of its tet's
+  4 vertices, **253 722/253 722**, against a 0.07–2.2 % random-face control;
+  portal cost equals the distance between face centroids, **380 460/380 460**.
+  ⚠️ **The base is `chunk + 0x10`, and my offsets on this page were 16 bytes
+  early** — the plane fields happened to land on the same bytes, so that
+  arithmetic survives, but the record boundary moves. My "13 467/13 467 points
+  inside the bbox" was **not evidence**: a shift inside a homogeneous `f32`
+  array yields other floats from the same array, so the test passes either way.
   See [`structures/regn-map-grid.md`](structures/regn-map-grid.md).
+  ❔ Still open there: the **runtime consumer** (not reached; a `float4`-aligned
+  header read with VMX loads leaves no displacement signature to search for).
 * 🔴 **`hidden/DefTables.pak` is NOT it** (checked 2026-08-24). The three
   unnamed schemas are more **model/render** tables in the same vocabulary as the
   named ones — `7e66225f` (283 objects) carries `RenderFrameModel`,