@@ -123,7 +123,7 @@ Budget-conformance props. Not examples. Conventions: [`showcase/README.md`](show
   <a href="showcase/park-bench/"><img src="showcase/park-bench/preview.webp" width="24%" alt="Park bench: a wrought-iron bench whose round-bar legs curl into scrolled feet, with wooden slats and a reclined back, on a dark studio floor" /></a>
   <a href="showcase/wheelbarrow/"><img src="showcase/wheelbarrow/preview.webp" width="24%" alt="Wheelbarrow: a wooden tray with walls of stacked boards and iron straps, a spoked wheel, rear legs, and handles on a dark studio floor" /></a>
   <a href="showcase/anvil/"><img src="showcase/anvil/preview.webp" width="24%" alt="Anvil: a forged-steel London-pattern anvil with a hammer-polished face on a hooped timber stump, a hammer at its foot" /></a>
-  <a href="showcase/water-trough/"><img src="showcase/water-trough/preview.webp" width="24%" alt="Water trough: a watertight wooden trough with plank ends, rippled water, rust-streaked iron straps and trestle legs on a dark studio floor" /></a>
+  <a href="showcase/water-trough/"><img src="showcase/water-trough/preview.webp" width="24%" alt="Water trough: a staved wooden trough on pegged trestle legs, iron straps bolted and clipped over the rim, rippled water inside and a bung in one end" /></a>
   <a href="showcase/hitching-post/"><img src="showcase/hitching-post/preview.webp" width="24%" alt="Hitching post: a square timber post with a pyramidal cap, a cross-arm on two knee braces with iron end caps, iron bands wrapped around it, two hitching rings and a nailed horseshoe on a dark studio floor" /></a>
   <a href="showcase/grindstone/"><img src="showcase/grindstone/preview.webp" width="24%" alt="Grindstone: a sandstone wheel dipping into a water-filled trough on a timber A-frame, with iron axle, hubs and a crank turned toward the viewer, on a dark studio floor" /></a>
   <a href="showcase/hand-pump/"><img src="showcase/hand-pump/preview.webp" width="24%" alt="Hand pump: a green-enamelled cast-iron village pump with a fluted barrel, ball finial and counterweighted handle on a stepped wooden plinth, a hooped wooden bucket under its spout" /></a>
 
@@ -195,7 +195,7 @@
       "name": "water-trough",
       "dir": "showcase/water-trough",
       "teaches": "A procedural watertight water trough through UVs, bake, LOD, collider, and Unity glTF, asserting recomputed budgets rather than an API contract.",
-      "alt": "A staved wooden water trough with half-round ends built of three boards, on crossed trestle legs, half full of rippled dark water.",
+      "alt": "A staved wooden water trough on pegged trestle legs, iron straps bolted and clipped over its rim, half full of rippled dark water, a bung in one end.",
       "witnessesFix": "Recomputed: 3316 tris, three materials with 1482 wood, 156 metal and 29 water faces, UVs in 0..1 with zero AABB overlap, outer AABB 1.093x0.552x0.5055 m, zmin 0, four shoes planted, each end three lapped boards, end rim span 21 mm, strap BVH gap 0, water-hull gap 2.6 mm, water contained on 66 of 66 rays, hull 1.045x0.466 m, LOD ratios in band, convex collider 68 tris, non-empty glTF. --skip-decimate exits 9; --stray-vert 15; --lift-z/--short-legs 16; --box-ends 17; --float-strap/--open-ends 18; --narrow-hull 19; --slab-ends 20.",
       "hero": "docs/gallery/assets/water-trough-hero.webp",
       "preview": "showcase/water-trough/preview.webp",
 
@@ -1,8 +1,9 @@
 # Water trough
 
 A showcase piece, not an example. Procedural staved water trough on a
-timber stand (watertight U-hull, board-built ends, contained water, iron
-straps, trestle legs) then the shipped pipeline: unique-cell UVs, Cycles
+timber stand (watertight U-hull, board-built ends with a drain bung,
+contained water with a rippled surface and meniscus, iron straps
+through-bolted and clipped over the rim, pegged trestle legs) then the shipped pipeline: unique-cell UVs, Cycles
 high-to-low normal bake, LOD chain, convex collider, Unity glTF export.
 
 The hull, ends, straps and water all sample the same YZ arc. Each end
@@ -23,31 +24,41 @@ witness an API contract. "It rendered without error" is not a check.
 Hygiene combinatorics match `examples/mesh-hygiene-audit` (copied, not
 imported).
 
-Intended size: 1.08 m tray length, 0.44 m across the U, 0.50 m overall
-height; outer AABB 1.093 × 0.552 × 0.5055 m.
+Intended size: 1.08 m tray length, 0.44 m across the U, 0.51 m overall
+height; outer AABB 1.111 × 0.552 × 0.512 m (the bung adds 18 mm in X, the
+rim clips 7 mm in Z).
 
 ## Budgets
 
 Declared as named constants; every gate **recomputes** from the mesh,
 materials, UVs, evaluated LOD, collider, or export file.
 
-| Axis | Declared | Measured (4.5.11 / 5.1.2 / 5.2.1) |
+| Axis | Declared | Measured (4.5.11 / 5.2.1) |
 | --- | --- | --- |
-| Base triangles | 2800–3500 | 3316 / 3316 / 3316 |
-| LOD1 ratio | 0.32–0.62 of base | 0.5000 / 0.5000 / 0.5000 |
-| LOD2 ratio | 0.10–0.35 of base | 0.2195 / 0.2195 / 0.2195 |
-| Materials | exactly 3 distinct; ≥24 wood, ≥24 metal, ≥6 water | 3 slots; 1482 / 156 / 29 |
+| Base triangles | 4300–5200 | 4792 / 4792 |
+| LOD1 ratio | 0.32–0.62 of base | 0.5000 / 0.5000 |
+| LOD2 ratio | 0.10–0.35 of base | 0.2199 / 0.2199 |
+| Materials | exactly 3 distinct; ≥24 wood, ≥24 metal, ≥6 water | 3 slots; 1656 / 420 / 476 |
 | UVs | in `0..1`, AABB overlap ≤ 1e-5 | in range, overlap 0 |
-| Outer AABB | (1.093, 0.552, 0.5055) m ± 0.01 | (1.0932, 0.5520, 0.5055), zmin 0 |
-| Collider tris | ≤ 80 | 68 |
-| Export | written, size > 0 | 242240 / 242240 / 242224 bytes |
+| Outer AABB | (1.111, 0.552, 0.512) m ± 0.01 | (1.1112, 0.5520, 0.5123), zmin 0 |
+| Collider tris | ≤ 80 | 76 |
+| Export | written, size > 0 | 355404 / 355388 bytes |
 
 Base triangles rose from **2484 to 3700** in the first quality pass: box
 end slabs and a single extruded U became ten jittered staves, U end-caps,
 continuous straps offset from the legs, and stretchers that meet the
 inner faces. The second pass took them to **3124**: the open U-band ends
 became solid end boards, which close the section with fewer faces. The
-third pass took them to **3316**: each end became three boards.
+third pass took them to **3316**: each end became three boards. The
+fifth pass took them to **4792**: the water became a lofted, rippled
+volume (~900 triangles; it was one flat quad on a U prism), and the
+straps gained ten bolt heads and four rim clips, the trestles six pegs,
+and the right end a bung. The band moved from 2800–3500 to 4300–5200, the
+same ~±10 % slack around the measured count. The collider hulls the
+trough without the sub-2 cm hardware (bolts, pegs, bung): detail that
+small carries no collision meaning. The rim clips are 47 mm wide and
+stay in it. The 5.1.2 column was dropped with this change: the new model
+was measured on 4.5.11 and 5.2.1 only.
 
 DECIMATE COLLAPSE triangle counts are **not** identical across series —
 the gate is a ratio band, not an exact count. Bake pixels are
@@ -82,9 +93,10 @@ Recomputed from the generated mesh, not asserted about the script.
 | --- | --- | --- |
 | End-cap rim Z-span (union of an end's boards) | ≤ 0.080 m | 0.0208 |
 | Strap-to-hull BVH gap | ≤ 0.008 m | 0.00000 |
-| Water-to-hull BVH gap | ≤ 0.008 m | 0.00260 |
-| Water contained by the end boards | 0 misses over 66 outward rays | 0 of 66 |
+| Water-to-hull BVH gap | ≤ 0.008 m | 0.00249 |
+| Water contained by the end boards | 0 misses over 120 outward rays | 0 of 120 |
 | **End boards** per end | ≥ 3 | 3 |
+| Bolt bite: each of the 10 bolt heads' deepest vertex inside its strap (signed depth) | ≥ 0.002 m, exactly 10 bolts | 0.00347 |
 
 ### Why the ends are solid boards
 
@@ -100,8 +112,8 @@ hull; nothing asked whether anything held it in at the ends.
 along X, from the face's perimeter vertices and from points drawn 50% and
 90% of the way in from the centroid, so the middle of the section is
 tested and not only the rim a band would cover. Every ray must hit
-timber within `1.5 × END_T`. `--open-ends` restores the U-bands: all 66
-rays miss, and the piece exits 18.
+timber within `1.5 × END_T`. `--open-ends` restores the U-bands: 119 of
+the 120 rays miss, and the piece exits 18.
 
 ### Why each end is three boards
 
@@ -138,12 +150,23 @@ The third pass darkened the grazing tint from a pale grey-blue (0.20,
 the surface near grazing, where that tint wins, and it read as a
 painted slab.
 
+The fifth pass made the surface geometry. The water is lofted along X,
+`WATER_NX` stations with `WATER_NY` strips across each, under two crossing
+standing waves of `RIPPLE_AMP` that damp to zero at the staves, and a
+`MENISCUS_H` meniscus that climbs the wall over `MENISCUS_W`. The water is
+the one smooth-shaded material, so the key light runs along the crests.
+The straps were invisible from the hero camera, which looks over the rim
+while the straps wrap the hull's underside. Each strap now ends in a clip
+hooked over the rim and carries five domed carriage-bolt heads. The
+trestle legs are pegged through their stretcher tenons, and a drain bung
+sits low in the right end.
+
 The fourth pass made the surface read as liquid rather than as a teal panel: larger ripples (noise scale 22 to 7) under a stronger bump (0.08 to 0.30) at roughness 0.03 catch the key as glints, and the render path turns on EEVEE screen-space raytracing (4.2+) so the staves mirror in the water. The iron gets vertically stretched rust runs that dull its metallic response. A lower camera was tried to show the hull straps and rejected: the water surface dropped out of view.
 
 ### Falsifiers
 
-Each violates one named budget. All nine were run on 4.5.11, 5.1.2 and
-5.2.1 and returned the same code on each.
+Each violates one named budget. After the fifth pass all ten were re-run
+on 4.5.11 and 5.2.1 and returned the same code on each.
 
 | Flag | Budget violated | Exit |
 | --- | --- | --- |
@@ -152,10 +175,11 @@ Each violates one named budget. All nine were run on 4.5.11, 5.1.2 and
 | `--lift-z` | bounding box `zmin` is 0 | 16 |
 | `--short-legs` | named shoe supports at Z=0 | 16 |
 | `--box-ends` | end-cap rim span | 17 |
-| `--float-strap` | strap-to-hull gap | 18 |
+| `--float-strap` | strap-to-hull gap (straps lifted `STRAP_FLOAT` 0.012 m: gap 0.01169) | 18 |
 | `--narrow-hull` | hull plan vs stated size | 19 |
 | `--open-ends` | water contained by the end boards (restores the open U-band ends) | 18 |
 | `--slab-ends` | end boards per end (restores the one-piece D board; measures 1) | 20 |
+| `--float-bolts` | bolt bite (heads lifted 0.015 m off the strap: −0.01153) | 21 |
 
 `--short-legs` lifts the shoes and stretches each leg's foot down to the
 floor, so AABB `zmin` stays 0 (the legs still plant) and the
@@ -164,6 +188,12 @@ whole piece re-ground on the legs. That shrank the AABB by ~10 mm, 0.4 mm
 inside the bounding-box tolerance, and a 1.5 mm model change in this pass
 tipped it to exit 8. With the feet stretched, the envelope moves 1.6 mm.
 
+`--float-strap` lifted the straps 0.040 m until the fifth pass. With bolt
+heads and rim clips riding on the straps, that widened the AABB past its
+tolerance and the probe hit exit 8 before the strap-seat budget it exists
+for. It now lifts them `STRAP_FLOAT` (0.012 m), still a 0.0117 m gap
+against the 0.008 m budget.
+
 ## Run
 
 ```bash
@@ -177,6 +207,7 @@ blender --background --python water_trough.py -- --float-strap
 blender --background --python water_trough.py -- --narrow-hull
 blender --background --python water_trough.py -- --open-ends
 blender --background --python water_trough.py -- --slab-ends
+blender --background --python water_trough.py -- --float-bolts
 blender --background --python water_trough.py -- --output trough.png
 ```
 
@@ -186,7 +217,7 @@ Smoke passes no flags.
 
 File-local. `9` is a valid check code. `10` is reserved for
 `gallery_framing.check_framing` on the `--output` path. `15`–`19` are the
-hygiene and joint-fit family.
+hygiene and joint-fit family; `20`–`21` are file-local.
 
 | Code | Meaning |
 | --- | --- |
@@ -211,3 +242,4 @@ hygiene and joint-fit family.
 | 18 | Seat: strap or water BVH gap (`--float-strap`), or water not contained by the end boards (`--open-ends`) |
 | 19 | Hull length or width off the stated real-world size (`--narrow-hull`) |
 | 20 | An end is fewer than three boards (`--slab-ends`) |
+| 21 | Bolt seat: a bolt head not inside its strap, or not exactly ten (`--float-bolts`) |