PROCITY/C-progress.md

# LANE C — INTERIORS · progress (PROCITY-C)

*Status: **v1 complete & verified**. Standalone interiors library + test page. Every shop door opens
into a unique, seeded, themed interior, generated on demand in ~4ms, byte-identical every revisit.*

Last updated: 2026-07-14 (round 6) · owner: PROCITY-C · reviewer: Fable

---

## Update 2026-07-14 (round 6) — C1 interior draw batching (≤350 draws/room is law)

Round-6 §Lane C task 1 (the review debt: book room was 1,245 draws GLB-on). **Diagnosed** the two
drivers — (a) multi-material stock boxes cost one draw PER face (6×), (b) one mesh per stock item —
then batched (new `web/js/interiors/batch.js`):
- **stock.js**: boxes are now single-material; every stock mesh tagged `userData.isStock`.
- **batch.js** (`batchRoom`, called from interiors.js before the GLB upgrade): two-tier merge —
  room-level merge of all `isStock` across every fitting (grouped by material, world transforms baked)
  + per-fitting merge of fixture frames (kept in-group so bins stay raycast targets and the GLB
  upgrade can hide the fixture). `mergeGeometries` from vendored BufferGeometryUtils.
- **glb.js**: frame-hide is now by `isStock` tag (not frame-count), so batched fixtures hide and the
  room-level stock rides on the GLB.

**Result** (drawSweep, all 9 types × 6 archetypes, seed 1990):
- GLB-off worst **152** (opshop/hall), GLB-on worst **313** (opshop/hall) — book 1,245 → **189**. **≤350 ✓**.
- Determinism 0 fails / 810 builds · leak-free · dig still riffles batched bins (bins keep frame as hit
  target; dig regenerates its own sleeves) · worst warm build 38ms (<50) · visually identical.
- **Sweep now ASSERTS ≤350** (`drawSweep()` in the test page, folded into the soak; `window.PROCITY_C.
  drawSweep` for F's harness — see LANE_C_NOTES for the hook).

**C2 — map the 3 orphaned fittings** (published R5, unconsumed). In `glb.js`: `glassCase→glass_case`,
`magazineRack→magazine_rack`, and a NEW `crateStack` primitive (stack of crates) → `crate_stack`.
Recipe placements: crateStack in record + opshop (back-room dressing), glassCase added to milkbar,
magazineRack added to pawn (+ moved milkbar's magazineRack window→wall to dodge the door-counter).
Also **fixed `placeNearCounter`** — it picked one random side and gave up, so counter-zone fittings
(the glass case) rarely landed; now it tries both sides + offsets, then falls back to a free aisle spot.
All 3 load + render planted/scaled/facing right (yaw 0). Appearance: glassCase **12/12** (toy/pawn/milkbar),
magazineRack **12/12** (milkbar/pawn), crateStack ~11/12 (record/opshop). Contact sheet:
[glb_orphans_r6.jpg](docs/shots/laneC/glb_orphans_r6.jpg). drawSweep still ≤350 with them on (worst 177
GLB-on). **C3**: dig soak re-run after batching + new fittings — riffle works on batched bins, leak-free.

**Round 6 complete for Lane C**: C1 (batching, `35981ad`) + C2/C3 (orphans + dig re-verify) committed.
Draw law satisfied (≤313 was the tightest; ≤177 after C2), determinism/leak/dig all green, qa strict green.

---

## Update 2026-07-14 (round 5) — C1 v1.1 re-map (record_crate + counter_till) · **F can tag v1.1**

Round-5 §Lane C task 1 (the v1.1 gate). Lane E's re-exports mapped + validated in `glb.js`:
- `record_crate` fixed → record bins/crates upgrade to plastic crates with the procedural sleeves.
- `counter → 'counter_till'` (the real ~1.6 m counter-with-till). Keeper-stand pose unaffected.
- **Double-till resolved**: cash_register attach dropped when counter_till is live (it has its own till);
  falls back on the primitive; milkshake_mixer stays on the milk-bar bench (lifted to the GLB height).
- Sweep + soak (GLB on): `0 throws / 0 path / 0 det / leak-free / worst 10.4ms`; **0 double tills**.
  Primitive path unchanged (glb.js-only edit). Contact sheet: [glb_v1_1_r5.jpg](docs/shots/laneC/glb_v1_1_r5.jpg).
- Report + decision detail: [LANE_C_GLB_VALIDATION.md](docs/LANES/LANE_C_GLB_VALIDATION.md); F note in
  [LANE_C_NOTES.md](docs/LANES/LANE_C_NOTES.md). **→ F: C1 committed, v1.1 can be tagged.**

**C2 — `?dig=1` crate-riffle (v2, behind flag).** Ported 90sDJsim `dig.js` → `web/js/interiors/dig.js`:
walk to a record bin, press **E**, riffle its sleeves (scroll/drag), click the front to pull, **BUY IT**
(STUBBED — toast + remove; getCash constant; real economy is round 6+). Riffle items are seeded per bin
via the `stockAdapter(shop,'sleeve')` seam (procedural fallback now — parody 90s-AU sleeves). Own scene +
camera, procedural fwip/thunk audio, **leak-free** (per-open resources freed on close → dig soak 20×
`leakGeo 0 / leakTex 0`). Flag-off (`?dig=0`) is **byte-identical** — `buildInterior` is untouched; the dig
is wired only in the test page (F owns the shell seam — hook documented in LANE_C_NOTES §"input/mode hook").
Shot: [dig_riffle_r5.jpg](docs/shots/laneC/dig_riffle_r5.jpg).

**C3 — interior re-measure after Lane E's bake (`c522464`).** E baked the 6 heavy hero props to ≤8k tris.
Re-measured every interior (cache-busted to bypass the dev browser's stale HTTP cache): **record 43.6k**
(the C3 target, ~273k pre-bake), **milkbar 38.9k** (was the flagged 468k → over-budget flag CLOSED), all
rooms ≤107k tris. `book` is the draw-call outlier (1,245 draws from ~9 bookshelf GLBs + primitive spines) —
tris fine, interiors render one-at-a-time so gate 3 unaffected; instancing spines is the future lever.
Full table in [LANE_C_GLB_VALIDATION.md](docs/LANES/LANE_C_GLB_VALIDATION.md §C3).

**Round 5 complete for Lane C**: C1 (v1.1 re-map) + C2 (`?dig=1`) + C3 (re-measure) all committed.

---

## Update 2026-07-14 (round 4) — hero props into rooms

Round-4 task (ROUND4_INSTRUCTIONS §Lane C): map the 4 new hero props + cash_register (manifest now 14
fittings), sweep/soak with them on, screenshot each, delete the stale `_local_glb/`, measure a hero
room. **All done.** Full report for Lane E: [LANE_C_GLB_VALIDATION.md](docs/LANES/LANE_C_GLB_VALIDATION.md);
contact sheet [docs/shots/laneC/glb_heroprops_r4.jpg](docs/shots/laneC/glb_heroprops_r4.jpg).

- **New mappings** (`glb.js`): `arcade_cabinet`→new `arcadeCabinet` primitive (video focal prop),
  `listening_booth`→`listeningCorner` (record), `drinks_fridge`→`fridge` (milkbar). All load, `glb_law`
  compliant, yaw 0 (no correction). A new **counter-top attach** (`attachCounterTop`) puts `cash_register`
  on every counter's till slot (hides the primitive till) and `milkshake_mixer` on the milk-bar benchtop —
  the counter primitive + keeper stand are untouched.
- **Focal-prop reliability fix**: the door-counter path loop was pulling priority-4 focal props (arcade
  appeared in only 5/24 video rooms). Raised the 3 focal props to priority 6 + placed-first →
  **24/24 appearance**, still 0 carves / 0 path-fails.
- **Validation**: primitive sweep 810 builds `{throws 0, pathFail 0, detFail 0}`; GLB-on soak
  `{throws 0, path 0, det 0, leakGeo 0, leakTex 0, worst 7.3ms}`; all 5 new props confirmed in-room.
- **Room tris measured** (task 4): milk-bar GLB-on ≈ **468k tris** (over budget) driven by `drinks_fridge`
  (77k) + `milkshake_mixer` (73k) — **reported to Lane E** as the #1 bake-pass target (not fixed, per
  integrator decision #2; interiors render one-at-a-time so gate 3 / the street budget is unaffected).
- **Cleanup**: deleted `web/assets/_local_glb/` (R3 validation copy); test page now loads GLBs via the
  live `depot:` path (`?localdepot=1` still works for offline). `localBase` hook kept in `glb.js`.
- **Standby (C task 5)**: when Lane E re-exports `record_crate` (broken) + a ~2 m counter-with-till, I
  re-map both. Not landed at commit time.

---

## Update 2026-07-14 (round 3) — GLB hero-prop visual validation

Round-3 task (ROUND3_INSTRUCTIONS §Lane C): flip `useGLB` on and validate Lane E's fitting GLBs in real
rooms. Done — full report for Lane E in [docs/LANES/LANE_C_GLB_VALIDATION.md](docs/LANES/LANE_C_GLB_VALIDATION.md).

**Verdict:** 5 of 9 fitting GLBs are good and now live behind `useGLB` (wire_shelf, clothes_rack,
bookshelf, cube_shelf_wide, work_table); 2 fall back to primitive with a report filed
(`record_crate` **broken — won't load**; `counter` **too long/no till** → primitive keeps the till +
keeper stand). record bins stay primitive until Lane E re-exports the crate.

**Soak with `useGLB` on** (50 rooms, all types): `throws 0 · pathFail 0 · determinismFail 0 · leakGeo 0 ·
leakTex 0 · worst build 10.5ms · 256 upgrades applied` — GLB resources dispose leak-free on room exit.

**glb.js changes (my file):**
- `manifest.localBase` — load GLBs from a served local dir for offline validation (production still uses
  `depot:<file>`; forward-compatible with Lane E's local-depot mode).
- **Real-metre scale, clamped** to the reserved footprint (was fit-to-width, which squashed tall props);
  matches `glb_law` (metres). Per-kind **yaw correction** (`KIND_TO_YAW`) for the Z-major assets
  (bookshelf/cube/work_table need +90°) per the manifest `facing` convention ("Lane B/C rotate directional props").
- `room.glbReady` (interiors.js) — a promise that resolves when GLB swaps settle, so callers can await
  before screenshot/leak-check (Lane F can use it in the §3.4 wiring).
- Test page (`interior_test.html`) gains a **GLB props** toggle + a `GLB props: N upgraded` HUD line.
  Local validation needs the GLBs copied in: `cp pipeline/_normalized/procity_fit_*.glb web/assets/_local_glb/`
  (untracked; real GLBs live on the depot). Screenshot grid: [docs/shots/laneC/glb_validation_grid.jpg](docs/shots/laneC/glb_validation_grid.jpg).

---

## Update 2026-07-14 (b) — keeper stand pose (resolves Lane F §8 · unblocks §3.2/§3.3)

Lane F's runbook asked (LANE_F_NOTES §8): *"does `places` tag the counter slot with a stable
`kind:'counter'` so keepers find it?"* **Yes** — the counter interactable has always carried
`mesh.userData.kind === 'counter'` (+ `interactable:true`). But Lane D's keeper needs more than a
tag: `keepers.spawn(group,{x,z,ry})` needs *where the shopkeeper stands and which way it faces*
(keepers.js:28 — "`ry` = the counter's outward facing"). I computed the customer-facing side
internally but never surfaced it — so Lane D would have read the bench's raw transform and stood a
keeper embedded in the counter, possibly facing a wall. Closed that gap (my files only, purely additive):

- **New: `room.counter = { mesh, pose:{x,z,ry}, stand:{x,z,ry} }`** (interiors.js). `pose` is the
  bench; **`stand` is the keeper pose** — behind the bench on the service side, facing the customer,
  clamped inside the room, in **room-local space** (the same space Lane D adds the keeper into via
  `interior.group`). `ry` uses the rig-front = local −Z convention keepers.js expects.
- **The same `{x,z,ry}` also rides the counter interactable**: `place.userData.keeperStand` — for the
  `places`-iteration path Lane D/F described. Deep-equal to `room.counter.stand`.

**Lane D/F wiring (drop-in for §3.2/§3.3):**
```js
const room = buildInterior(shop, THREE);
const s = room.counter.stand;   // or: room.places.find(p=>p.userData.kind==='counter').userData.keeperStand
keepers.spawn(room.group, { ...s, shopId: shop.id, type: shop.type });
// on exit: keepers.remove(handle) / keepers.disposeAll(), then room.dispose()
```

Verified in-browser (9 types × 4 seeds = 36 builds, + 50-room soak):
`stand in-bounds ✓ · faces-customer ✓ (dot>0 for all) · places-carries-keeperStand ✓ (deep-equal) ·
stand deterministic ✓ · placement determinism unchanged ✓ · soak avg 3.6ms / worst 7.7ms · leak geo0 tex0 ·
pathFail 0 · every room has a counter+stand`. No change to layout/placement of existing rooms.

**Minor known cosmetic (corner counters):** a corner counter sits ~0.55 m off the east wall, so the
service gap (~0.25 m) is narrower than a person — the keeper stands *at* the till with a small hidden
overlap into the solid waist-high bench (torso reads above the counter, legs behind it). Facing and
side are correct; it reads as "keeper at the till." If Lane D/Fable want real standing clearance I can
nudge corner counters ~0.2 m off the wall — but that changes those rooms' committed placement +
screenshots, so it's a decision, not a bug.

**Two contract-drift corrections for the F runbook** (§2's Lane-C line was written against an earlier
draft of my API): (1) there is **no `opts.registry`** — registry override is the one-time global
`mergeRegistry(registry)` (a per-build registry mutation broke same-seed determinism; removed in the
review pass). (2) `recipe.counterPos` is a **placement-strategy string** (`door|forward|back|corner`),
**not** a world position — use `room.counter.stand` for the keeper pose.

---

## What shipped

All files under my lane's ownership (`web/js/interiors/*`, `web/interior_test.html`) — no other lane's
files touched. Lane A's `core/registry.js` hadn't landed, so the lane is **fully standalone** (its 9
type recipes live in `theme.js`) with a `mergeRegistry()` hook for Lane F to wire the registry later.

| file | role |
|---|---|
| [interiors.js](web/js/interiors/interiors.js) | **public API** — `buildInterior(shop, THREE, opts)` |
| [theme.js](web/js/interiors/theme.js) | 9 shop-type recipes (archetype/wallpaper/floor bias, clutter, counter pos, fittings mix, stock kind, signage) + aliasing + registry-override hook |
| [shell.js](web/js/interiors/shell.js) | room shell: floor/walls/ceiling from lot×archetype, glazed shopfront + street backdrop, blocked back doorway, interior lighting |
| [fittings.js](web/js/interiors/fittings.js) | parametric fittings kit (ported from 90sDJsim + extended): bins, crates, racks, 4 shelf types, VHS aisle, glass case, counter+till, fridge, magazine/spinner racks, armchair, escalator, pegboard, barred window, returns slot, art frames |
| [layout.js](web/js/interiors/layout.js) | the placer: per-archetype zones, shuffled wall-slot system, occupancy grid, **guaranteed door→counter flood-fill path** |
| [stock.js](web/js/interiors/stock.js) | v1 visual stock: pooled canvas-texture sleeves/spines/boxes/garments/snacks with price stickers (dig.js trick) + `stockAdapter` hook for BaseGod data |
| [context.js](web/js/interiors/context.js) | build/dispose/seed backbone: independent seeded sub-streams, shared-geometry cache, leak-free `disposeAll()` |
| [glb.js](web/js/interiors/glb.js) | **optional** GLB hero-prop upgrade — reads Lane E's `manifest.json`, swaps primitives for depot GLBs, placeholder-persists. OFF by default; primitive fallback always |
| [interior_test.html](web/interior_test.html) | standalone test page (below) |

## Public API (the contract Lane B/F build against)

```js
import { buildInterior } from './js/interiors/interiors.js';
import * as THREE from 'three';

const room = buildInterior(shop, THREE, opts?);
scene.add(room.group);
// … player walks; on hitting room.exits[i], fire procity:exitShop …
room.dispose();               // frees ALL per-room GPU resources; removes group from parent

// room = {
//   group,                              // THREE.Group, self-contained (lights included)
//   spawn: { x, z, ry },                // enter just inside the door, facing −Z (into the shop)
//   exits: [ { x, z, w, toStreet } ],   // door back to street
//   places: [ …meshes w/ userData ],    // interactables: counter, bin, case, fridge, returns, exit
//   counter: { mesh, pose, stand },     // pay point. stand:{x,z,ry} = keeper (Lane D) spawn pose
//   dims: { W, D, H, archetype, type },
//   placement,                          // deterministic summary (deep-equal per seed)
//   pathOK, buildMs, counts(), dispose()
// }
```

`shop` is tolerant — recognized fields `{ id, type, name, seed, storeys, lot:{w,d} }`:
- **seed** (uint32) is the ONLY randomness source; falls back to a hash of id/name/type if absent.
- **type** — any CITY_SPEC type (`record opshop toy book video pawn milkbar dept stall`) **or** a
  thriftgod/Overpass alias (`music charity pawnbroker market video_games …`); defaults to `opshop`.
- **lot** `{w,d}` metres — the room adapts to it (never exceeds it); absent → archetype ranges decide.
- **storeys** drives ceiling height 3.2–4.5m.
- `opts`: `{ archetype?: 'cosy'|'gallery'|'wide'|'hall'|'pokey', stockAdapter?, useGLB?, manifest?, manifestUrl? }`.
  Registry override is a **one-time global** — `import { mergeRegistry } from interiors.js; mergeRegistry(registry)`
  at init (NOT a per-build opt — a per-call mutation of the shared recipe table would break same-seed determinism).

**Coordinate convention** (shared with a future Lane B wiring): `+Z` = door/street side, `−Z` = back,
origin = room centre, floor `y = 0`. Everything is in the returned `group`'s local space.

### For Lane B (door wiring, later)
`buildInterior` is a pure function — call it on `procity:enterShop`, add `room.group` to the scene,
teleport the player to `room.spawn`. On `procity:exitShop` (player reaches `room.exits[0]`) call
`room.dispose()` and restore the street. The street window fake is Lane B's; I own the inside view
(a bright canvas street backdrop plane is already behind the glazing).

### For content phase (BaseGod / GODVERSE)
Pass `opts.stockAdapter = (shop, slotKind) => ({ texture }) | ({ mesh }) | null`. Returning a texture
skins that stock item's face; a mesh replaces the item; null → procedural placeholder. No layout/
fittings changes needed. `slotKind ∈ { sleeve, spine, box, snack, magazine, garment, treasure }`.

## Test page — `web/interior_test.html`

Serve: `cd web && python3 -m http.server 8130` → open `/interior_test.html`.
- seed input · type dropdown (9) · archetype override (auto + 5) · lot `w×d`/auto · re-roll · seed ±
- first-person walk (PointerLock + WASD) with occupancy-grid collision + room clamp
- debug toggles: **wireframe** (F), **occupancy grid** (G), **path** (spawn/counter markers)
- **▶ 50-room soak test**: builds+disposes 50 seeded rooms, asserts ms/room, leaked geometries vs
  baseline, and determinism (same seed → identical placement)

## Acceptance — all met

| requirement | result |
|---|---|
| Same seed twice → identical room (deep-equal placement) | ✅ 0 mismatches / 810 builds |
| All 9 types × 5 archetypes render sensibly | ✅ contact sheet `docs/shots/laneC/_grid_9types_5archetypes.jpg` |
| Build < 50ms/room | ✅ steady-state ~4ms, clean-soak worst ~8ms (first-ever build ~60ms one-time cold-JIT; occasional ~60ms GC pauses only under back-to-back torture loops — not a real per-room cost) |
| Dispose leak-free (info.memory → baseline) | ✅ soak leak: geo 0, tex 0 |
| Flood-fill door→counter always exists | ✅ 0 path-fails, 0 carves / 810 builds |
| Runs with zero assets & zero network | ✅ seeded flat-colour fallback under every texture; map only assigned on load |

**Full sweep** (9 types × {auto+5 archetypes} × 3 seeds × {null,4×4,5×14,20×20,3×3} lots = 810 builds):
`throws 0 · pathFail 0 · determinismFail 0 · carved 0`. Warm perf: all < 50ms (worst 33.2ms).
**Soak** (50 rooms): `avg 4.0ms · worst 9.6ms · leakGeo 0 · leakTex 0 · detFail 0 · pathFail 0`.

## Key decisions & notes for review

- **90sDJsim `fittings.js` ported** (it was written to be lifted): `clothesRack`, `shelfUnit`,
  `recordBin`, `table`, `counter`, `pegboard`, garment-silhouette canvas trick. Extended with the
  fittings CITY_SPEC's registry needs (cube/metal/book/VHS shelving, glass case, fridge, spinner,
  magazine rack, armchair, escalator prop, returns slot, barred window, listening corner).
- **thriftgod `buildShop` ported**: the 5 archetypes, the shuffled wall-slot system, bins with fanned
  sleeves wearing covers, corner counter+till, crooked wall art, blocked back doorway.
- **Determinism** via independent seeded sub-streams keyed by a salt string (`ctx.stream('wallpaper')`
  etc.) so adding a fitting in one subsystem never shifts another subsystem's picks.
- **Leak-free** via a tracked build context: per-room geometry/material/CanvasTexture/tiled-file-texture
  are freed in `dispose()`; globally-cached file textures (`core/loaders.loadTex`) are shared and not
  disposed (bounded cache). Dispose-before-texture-load race is guarded (`_disposed`).
- **Perf**: shared-geometry cache (`ctx.boxGeo/planeGeo/cylGeo`) collapses the hundreds of identical
  stock items in a room down to ~80–110 geometries; spine density tuned so a book barn is ~600 meshes.
- **GLB upgrades**: `web/assets/manifest.json` (Lane E) is read if present, primitive fallback always.
  Not present yet → 100% primitives, which is why the test page runs asset-free.

## Integration with sibling lanes (landed in parallel)
- **Lane A `core/registry.js`** — its `SHOP_TYPE_IDS` match my 9 recipe keys exactly. I kept the
  interior recipes local (the registry doesn't carry archetype-bias/clutter/counter-pos/stock detail),
  with `mergeRegistry()` as the one-time override seam for Lane F.
- **Lane E `web/assets/manifest.json`** — its `fittings` section (9 depot GLBs with footprints) is now
  wired through `glb.js` (opt-in `useGLB`, primitive fallback). Depot GLBs may not be uploaded yet;
  verified the fallback (unreachable depot → primitives persist, no crash, no leak).
- **Lane D `citizens/keepers.js`** — its `keepers.spawn(group,{x,z,ry,shopId,type})` now has a clean
  source: `room.counter.stand` (also on `place.userData.keeperStand`). See the *Update (b)* section at
  the top. Verified the pose is on the service side, faces the customer, and is deterministic.

## Adversarial review — 5 findings, all fixed

Ran a 5-dimension adversarial multi-agent review (determinism / disposal-leaks / path-guarantee /
three-api / edge-robustness) with a per-finding verify pass. 5 real defects surfaced; all fixed and
re-verified (830-build sweep + 50-room soak green after each fix):

| # | sev | file | defect | fix |
|---|---|---|---|---|
| 1 | med | interiors.js | per-build `opts.registry` permanently mutated the shared recipe table → latent same-seed determinism break across differing registry states | removed per-build option; registry override is now a one-time global `mergeRegistry()` (Lane F setup) |
| 2 | low | interiors.js | explicit `null` opts threw (`opts = {}` default only covers `undefined`) | normalize `opts = opts \|\| {}` |
| 3 | low | shell.js | empty `archetypeBias` array → `bias[0][0]` on `[]` throws | fall back to uniform bias when missing **or** empty |
| 4 | med | layout.js | fittings pulled by the path loop left phantom interactables in `places` (dangling after dispose) | collect `places` from survivors at the end, not incrementally at placement |
| 5 | low | layout.js | `rebuildOcc` re-stamped wall-mounted fittings that `placeAtWall` never stamped → phantom floor obstacles after a blocker-pull | mark wall-mounted `noStamp`; skip in `rebuildOcc` **and** exclude from the removable pool |

Verify evidence (post-fix): `nullOpts ok · phantomPlaces 0/332 · determinismAcrossBuilds identical ·
emptyBias ok · sweep 810 {throws 0, pathFail 0, detFail 0} · soak {avg 4.2ms, worst 8ms, leakGeo 0,
leakTex 0}`. (Reviewers also confirmed no disposal/leak or three.js-contract defects.)

## Not done (out of scope for v1 / depends on other lanes)
- Real item data / economy (content phase — `stockAdapter` hook is ready).
- GLB hero props are **wired** (`glb.js`, opt-in) but not visually validated end-to-end — needs the
  depot GLBs actually uploaded (Lane E) + `useGLB` flipped on by Lane B/F. Primitive path is the tested baseline.
- Interior-mapping shader for street windows (Lane B stretch goal).
- Back-room beyond the blocked doorway (v2).