diff --git a/README.md b/README.md
index 7615d66..18d0911 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,12 @@ persistence (`parks/`, `assets/uploads/`).
 
 - **TRANSITION** — quarter (escalating radius, lump, vert extension), hip/corner quarter,
   bank, kicker (tunable concavity), spine, roller/pump bump, mogul, volcano,
-  bowl (square pool or round). **STREET** — funbox, pyramid, ledge, wedge/manny pad
+  bowl (square pool or round), and the **CUSTOM BOWL**: a polygon pool where every rim
+  vertex is a draggable ball with its own depth slider. Inside corners = drag a vertex
+  in, hips = out, shallow-to-deep escalator = ramp the depths, waterfall = two close
+  vertices with different depths — one continuous carve, no seams by construction.
+  Auto **pool coping** (bullnose tube, exported as grindable ledge segments) and a
+  **tile band** baked into the ground texture. **STREET** — funbox, pyramid, ledge, wedge/manny pad
   (inclined), stairs, island. Click a piece, click the ground. Drag to move, `[` `]`
   rotate, `D` dupe, `⌫` delete, `⌘Z` undo, optional 0.5m grid snap (THPS style).
 - **STEEL** — rails are polylines: flatbar, square bar, down rail, kink, double-kink,
@@ -47,9 +52,10 @@ persistence (`parks/`, `assets/uploads/`).
 ## Park format
 
 `parks/*.json` — bounds, spawn, `elements` (parametric primitives evaluated by
-`js/parkmath.js`), `rails`, `gaps`, `letters`, `zones`, `decals`, `props`, optional
-`underlay`. `parks/paddo.json` is Paddington Skatepark ported from bookquoy — load it,
-ride it, remix it.
+`js/parkmath.js`), `rails` (polylines), `gaps`, `letters`, `zones`, `decals`, `props`,
+optional `underlay`. Premade parks: `parks/paddo.json` (Paddington Skatepark ported from
+bookquoy) and `parks/pool_demo.json` (THE POOLROOM — custom-bowl showcase, passes PARK
+CHECK clean). Load them, ride them, remix them.
 
 ## Export → BOOKQUOY
 
diff --git a/js/editor.js b/js/editor.js
index 6fcc187..6c37482 100644
--- a/js/editor.js
+++ b/js/editor.js
@@ -138,7 +138,16 @@ export function initEditor(container) {
         new THREE.MeshBasicMaterial({ color: 0xffd93b }));
       m.position.set(x, y, z); m.userData.handle = true; selGrp.add(m); return m;
     };
-    if (sel.type === 'element') loop(elementOutline(obj));
+    if (sel.type === 'element') {
+      loop(elementOutline(obj));
+      if (obj.kind === 'bowlpoly') {                    // rim vertices are draggable
+        const c = Math.cos(obj.rot || 0), sn = Math.sin(obj.rot || 0);
+        obj.pts.forEach((p, i) => {
+          const wx = obj.x + p.u * c - p.v * sn, wz = obj.z + p.u * sn + p.v * c;
+          handle(wx, 0.18, wz, true).userData.bowlPt = i;
+        });
+      }
+    }
     else if (sel.type === 'rail') {
       const pts = obj.pts.map(p => new THREE.Vector3(p.x, p.y, p.z));
       selGrp.add(new THREE.Line(new THREE.BufferGeometry().setFromPoints(pts), mat));
@@ -296,6 +305,8 @@ export function initEditor(container) {
     const hs = ray.intersectObjects(selGrp.children.filter(o => o.userData.handle));
     if (hs.length && hs[0].object.userData.railPt !== undefined)
       return { type: 'railPt', i: hs[0].object.userData.railPt };
+    if (hs.length && hs[0].object.userData.bowlPt !== undefined)
+      return { type: 'bowlPt', i: hs[0].object.userData.bowlPt };
     if (!p) return null;
     const P = ed.park, x = p.x, z = p.z;
     // 2. props (real raycast)
@@ -412,8 +423,8 @@ export function initEditor(container) {
     if (ed.tool) { if (p) place(p); return; }
     const hit = pick(ev, p);
     if (!hit) { ed.select(null); return; }
-    if (hit.type === 'railPt') {
-      drag = { kind: 'railPt', i: hit.i, moved: false };
+    if (hit.type === 'railPt' || hit.type === 'bowlPt') {
+      drag = { kind: hit.type, i: hit.i, moved: false };
       controls.enabled = false; snapshot(); return;
     }
     ed.select({ type: hit.type, id: hit.id });
@@ -435,6 +446,13 @@ export function initEditor(container) {
       pt.x = snapV(p.x); pt.z = snapV(p.z);
       rebuildRails(); rebuildSelection(); return;
     }
+    if (drag.kind === 'bowlPt') {                       // world -> bowl-local vertex
+      const c = Math.cos(obj.rot || 0), sn = Math.sin(obj.rot || 0);
+      const du = snapV(p.x) - obj.x, dz = snapV(p.z) - obj.z;
+      obj.pts[drag.i].u = +(du * c + dz * sn).toFixed(2);
+      obj.pts[drag.i].v = +(-du * sn + dz * c).toFixed(2);
+      requestGround(); rebuildRails(); rebuildSelection(); return;
+    }
     const nx = snapV(p.x + drag.grabDX), nz = snapV(p.z + drag.grabDZ);
     if (s.type === 'rail') {
       const dx = nx - obj.pts[0].x, dz = nz - obj.pts[0].z;
@@ -464,7 +482,7 @@ export function initEditor(container) {
     const obj = getSelected(); if (!obj) return;
     obj[key] = value;
     const t = ed.selection.type;
-    if (t === 'element') requestGround();
+    if (t === 'element') { requestGround(); if (obj.kind === 'bowlpoly') rebuildRails(); }
     if (t === 'zone' || t === 'decal') rebakeTexture();
     if (t === 'rail') rebuildRails();
     if (t === 'prop') rebuildProps();
diff --git a/js/parkbuild.js b/js/parkbuild.js
index 3bb1f9a..ad8cd44 100644
--- a/js/parkbuild.js
+++ b/js/parkbuild.js
@@ -2,7 +2,7 @@
 // so what you see in the editor is byte-for-byte what the game builds.
 import * as THREE from 'three';
 import { GLTFLoader } from 'three/addons/loaders/GLTFLoader.js';
-import { makeHeightAt, normalizeRail } from './parkmath.js';
+import { makeHeightAt, normalizeRail, bowlRimWorld } from './parkmath.js';
 import { makeBuiltinProp } from './props3d.js';
 
 export const GRID_RES = 0.5, GRID_PAD = 14;
@@ -40,6 +40,17 @@ export function bakeGroundTexture(park, x0, x1, z0, z1) {
     g.globalAlpha = zn.opacity ?? 1;
     g.fill(); g.restore();
   }
+  // pool detail: tile band + coping line traced around every custom-bowl rim
+  for (const e of park.elements || []) {
+    if (e.kind !== 'bowlpoly' || !e.tile) continue;
+    const rim = bowlRimWorld(e).map(([wx, wz]) => px(wx, wz));
+    for (const [w, color] of [[0.7 * PX, '#7fb4c9'], [0.22 * PX, '#e8e4d8']]) {
+      g.beginPath();
+      rim.forEach(([cx, cz], i) => i ? g.lineTo(cx, cz) : g.moveTo(cx, cz));
+      g.closePath();
+      g.strokeStyle = color; g.lineWidth = w; g.lineJoin = 'round'; g.stroke();
+    }
+  }
   const jobs = [];                                     // decals load async, re-bake per image
   for (const d of park.decals || []) {
     const img = new Image();
@@ -140,6 +151,23 @@ export function buildRails(park) {
       }
     }
   }
+  // bullnose pool coping around custom-bowl rims
+  const stone = new THREE.MeshStandardMaterial({ color: 0xe8e4d8, roughness: 0.7 });
+  const UP2 = new THREE.Vector3(0, 1, 0);
+  for (const e of park.elements || []) {
+    if (e.kind !== 'bowlpoly' || !e.coping) continue;
+    const rim = bowlRimWorld(e);
+    for (let i = 0; i < rim.length; i++) {
+      const [ax, az] = rim[i], [bx, bz] = rim[(i + 1) % rim.length];
+      const a = new THREE.Vector3(ax, 0.03, az), b = new THREE.Vector3(bx, 0.03, bz);
+      const len = Math.max(a.distanceTo(b), 0.01);
+      const bar = new THREE.Mesh(new THREE.CylinderGeometry(0.055, 0.055, len, 8), stone);
+      bar.position.copy(a).add(b).multiplyScalar(0.5);
+      bar.quaternion.setFromUnitVectors(UP2, b.clone().sub(a).normalize());
+      bar.userData.elId = e.id;
+      grp.add(bar);
+    }
+  }
   return grp;
 }
 
diff --git a/js/parkcheck.js b/js/parkcheck.js
index 16f8b7a..0243371 100644
--- a/js/parkcheck.js
+++ b/js/parkcheck.js
@@ -4,7 +4,7 @@
 import { makeHeightAt, elementOutline } from './parkmath.js';
 
 const STREET_KINDS = new Set(['ledge', 'funbox', 'stairs', 'pyramid', 'wedgepad']);
-const TRANNY_KINDS = new Set(['quarter', 'spine', 'bowl', 'bank', 'mogul', 'kicker', 'roller', 'corner', 'volcano']);
+const TRANNY_KINDS = new Set(['quarter', 'spine', 'bowl', 'bank', 'mogul', 'kicker', 'roller', 'corner', 'volcano', 'bowlpoly']);
 
 export function checkPark(park) {
   const out = [];
diff --git a/js/parkmath.js b/js/parkmath.js
index af51e2f..7a8f878 100644
--- a/js/parkmath.js
+++ b/js/parkmath.js
@@ -189,8 +189,62 @@ export const ELEMENT_KINDS = {
                      : Math.abs(u) < e.size && Math.abs(v) < e.size;
     },
   },
+  bowlpoly: {                           // modular pool: polygon rim, per-vertex depths.
+    // Inside corner = concave vertex, outside = convex, escalator = ramp the depths,
+    // waterfall = two close vertices with different depths. One continuous carve.
+    label: 'Custom Bowl',
+    defaults: {
+      pts: [{ u: 3.5, v: 0 }, { u: 2.2, v: 2.8 }, { u: -1.5, v: 3.2 },
+            { u: -3.8, v: 0.8 }, { u: -3.0, v: -2.4 }, { u: 0.8, v: -3.2 }],
+      depths: [1.2, 1.2, 1.5, 1.8, 1.8, 1.5],
+      coping: 1, tile: 1,
+    },
+    carve: true,
+    inside(e, x, z) {
+      const [u, v] = local(e, x, z);
+      return pointInPoly(u, v, e.pts);
+    },
+    height(e, x, z) {
+      const [u, v] = local(e, x, z);
+      const dB = distToPoly(u, v, e.pts);
+      // smooth floor: inverse-distance-weighted vertex depths (shallow end slopes to deep)
+      let sw = 0, swd = 0;
+      for (let i = 0; i < e.pts.length; i++) {
+        const du = u - e.pts[i].u, dv = v - e.pts[i].v;
+        const w = 1 / (du * du + dv * dv + 0.25);
+        sw += w; swd += w * (e.depths[i] ?? 1.5);
+      }
+      const D = swd / sw;
+      return -D + tranny(Math.min(dB, D), D);
+    },
+  },
 };
 
+function pointInPoly(u, v, pts) {
+  let inside = false;
+  for (let i = 0, j = pts.length - 1; i < pts.length; j = i++) {
+    const a = pts[i], b = pts[j];
+    if ((a.v > v) !== (b.v > v) &&
+        u < (b.u - a.u) * (v - a.v) / (b.v - a.v) + a.u) inside = !inside;
+  }
+  return inside;
+}
+function distToPoly(u, v, pts) {
+  let best = Infinity;
+  for (let i = 0; i < pts.length; i++) {
+    const a = pts[i], b = pts[(i + 1) % pts.length];
+    const du = b.u - a.u, dv = b.v - a.v;
+    const t = clamp(((u - a.u) * du + (v - a.v) * dv) / (du * du + dv * dv || 1), 0, 1);
+    best = Math.min(best, Math.hypot(u - (a.u + t * du), v - (a.v + t * dv)));
+  }
+  return best;
+}
+// world-space rim polygon (editor handles, coping tube, tile bake)
+export function bowlRimWorld(e) {
+  const c = Math.cos(e.rot || 0), s = Math.sin(e.rot || 0);
+  return e.pts.map(p => [e.x + p.u * c - p.v * s, e.z + p.u * s + p.v * c]);
+}
+
 // ---------------------------------------------------------------- rails
 // v2 rails are polylines: { id, name, kind:'rail'|'ledge', profile:'round'|'square',
 // pts:[{x,z,y},...] }. v1 {a,b,ya,yb} files normalize on sight. The GAME contract
@@ -212,6 +266,15 @@ export function flattenRails(park) {
       out.push({ name: r.name, a: [a.x, a.z], b: [b.x, b.z], ya: a.y, yb: b.y, kind: r.kind });
     }
   }
+  // pool coping rims are grindable steel: one ledge segment per rim edge
+  for (const e of park.elements || []) {
+    if (e.kind !== 'bowlpoly' || !e.coping) continue;
+    const rim = bowlRimWorld(e);
+    for (let i = 0; i < rim.length; i++) {
+      const a = rim[i], b = rim[(i + 1) % rim.length];
+      out.push({ name: 'Pool Coping', a, b, ya: 0.02, yb: 0.02, kind: 'ledge' });
+    }
+  }
   return out;
 }
 
@@ -290,6 +353,8 @@ export function elementHit(e, x, z) {
       return u * u + v * v < 1; }
     case 'bowl': { const [u, v] = local(e, x, z);
       return Math.abs(u) <= e.size + M && Math.abs(v) <= e.size + M; }
+    case 'bowlpoly': { const [u, v] = local(e, x, z);
+      return pointInPoly(u, v, e.pts) || distToPoly(u, v, e.pts) <= M; }
   }
   return false;
 }
@@ -325,6 +390,7 @@ export function elementOutline(e) {
       pts.push(W(Math.cos(a) * e.rx, Math.sin(a) * e.rz)); }
       return pts; }
     case 'bowl': return rect(-e.size, e.size, -e.size, e.size);
+    case 'bowlpoly': return bowlRimWorld(e);
   }
   return [];
 }
diff --git a/js/ui.js b/js/ui.js
index 368262e..575ce08 100644
--- a/js/ui.js
+++ b/js/ui.js
@@ -51,7 +51,8 @@ const PARAMS = {
 const PALETTE_GROUPS = [
   ['TRANSITION', [['quarter', 'QUARTER'], ['corner', 'HIP/CORNER'], ['bank', 'BANK'],
                   ['kicker', 'KICKER'], ['spine', 'SPINE'], ['roller', 'ROLLER'],
-                  ['mogul', 'MOGUL'], ['volcano', 'VOLCANO'], ['bowl', 'BOWL']]],
+                  ['mogul', 'MOGUL'], ['volcano', 'VOLCANO'], ['bowl', 'BOWL'],
+                  ['bowlpoly', 'CUSTOM BOWL']]],
   ['STREET', [['funbox', 'FUNBOX'], ['pyramid', 'PYRAMID'], ['ledge', 'LEDGE'],
               ['wedgepad', 'WEDGE PAD'], ['stairs', 'STAIRS'], ['dome', 'ISLAND']]],
 ];
@@ -215,6 +216,35 @@ export function initUI(ed) {
         (v, done) => ed.updateSelected('rot', +(v * DEG).toFixed(4), { done })));
       for (const [key, label, min, max, step] of PARAMS[obj.kind] || [])
         inspector.append(numRow(obj, key, label, min, max, step, upd(key)));
+      if (obj.kind === 'bowlpoly') {
+        inspector.append(el('div', 'ihint',
+          'drag the rim balls to shape it — inside corners, hips, whatever'));
+        obj.depths.forEach((d, i) => {
+          inspector.append(numRow({ d }, 'd', 'depth pt ' + (i + 1), 0.4, 3.4, 0.05,
+            (v, done) => { obj.depths[i] = v; ed.updateSelected('depths', obj.depths, { done }); }));
+        });
+        const vbtns = el('div', 'ibtns');
+        const addV = el('button', 'pbtn', '+ VERTEX');
+        addV.onclick = () => {
+          const a = obj.pts[obj.pts.length - 1], b = obj.pts[0];
+          obj.pts.push({ u: +((a.u + b.u) / 2).toFixed(2), v: +((a.v + b.v) / 2).toFixed(2) });
+          obj.depths.push(obj.depths[obj.depths.length - 1]);
+          ed.updateSelected('pts', obj.pts, { done: true });
+        };
+        const delV = el('button', 'pbtn', '− VERTEX');
+        delV.onclick = () => {
+          if (obj.pts.length <= 3) return;
+          obj.pts.pop(); obj.depths.pop();
+          ed.updateSelected('pts', obj.pts, { done: true });
+        };
+        vbtns.append(addV, delV); inspector.append(vbtns);
+        for (const [key, label] of [['coping', 'pool coping (grindable)'], ['tile', 'tile band']]) {
+          const cb = el('label', 'snaprow');
+          const inp = el('input'); inp.type = 'checkbox'; inp.checked = !!obj[key];
+          inp.onchange = () => ed.updateSelected(key, inp.checked ? 1 : 0, { done: true });
+          cb.append(inp, ' ' + label); inspector.append(cb);
+        }
+      }
       if (obj.kind === 'bowl') {
         const shape = el('select');
         shape.innerHTML = '<option value="0">square pool</option><option value="1">round bowl</option>';
diff --git a/parks/pool_demo.json b/parks/pool_demo.json
new file mode 100644
index 0000000..aa3a26b
--- /dev/null
+++ b/parks/pool_demo.json
@@ -0,0 +1,215 @@
+{
+ "name": "THE POOLROOM",
+ "bounds": {
+  "x0": -24,
+  "x1": 24,
+  "z0": -16,
+  "z1": 16
+ },
+ "slabColor": "#8f958f",
+ "grassColor": "#4d7c3c",
+ "spawn": {
+  "x": -18,
+  "z": 10,
+  "heading": 1.1
+ },
+ "elements": [
+  {
+   "id": "e2_bqff",
+   "kind": "bowlpoly",
+   "x": -8,
+   "z": 0,
+   "rot": 0,
+   "pts": [
+    {
+     "u": 5,
+     "v": 0
+    },
+    {
+     "u": 3.4,
+     "v": 4
+    },
+    {
+     "u": -2,
+     "v": 4.6
+    },
+    {
+     "u": -5.4,
+     "v": 1.2
+    },
+    {
+     "u": -4.4,
+     "v": -3.4
+    },
+    {
+     "u": 1.2,
+     "v": -4.6
+    }
+   ],
+   "depths": [
+    0.9,
+    0.9,
+    1.4,
+    2.2,
+    2.2,
+    1.4
+   ],
+   "coping": 1,
+   "tile": 1
+  },
+  {
+   "id": "e3_iu5u",
+   "kind": "quarter",
+   "x": 12,
+   "z": -16,
+   "rot": 0,
+   "len": 20,
+   "r0": 1.8,
+   "r1": 1.8,
+   "lump": 0,
+   "deck": 0.6,
+   "vert": 0
+  },
+  {
+   "id": "e4_fhid",
+   "kind": "kicker",
+   "x": 10,
+   "z": 6,
+   "rot": 3.141592653589793,
+   "len": 2.4,
+   "h": 0.7,
+   "run": 1.8,
+   "curve": 0.6,
+   "deck": 0.25
+  },
+  {
+   "id": "e5_g65t",
+   "kind": "roller",
+   "x": 16,
+   "z": 0,
+   "rot": 1.5708,
+   "len": 8,
+   "h": 0.45,
+   "s": 1.1
+  },
+  {
+   "id": "e6_dthi",
+   "kind": "ledge",
+   "x": 6,
+   "z": 12,
+   "rot": 0,
+   "hw": 1.5,
+   "hd": 0.8,
+   "h": 0.22
+  }
+ ],
+ "rails": [
+  {
+   "id": "rb",
+   "name": "Rainbow Rail",
+   "kind": "rail",
+   "profile": "round",
+   "pts": [
+    {
+     "x": 2,
+     "z": -10,
+     "y": 0.25
+    },
+    {
+     "x": 2.667,
+     "z": -10,
+     "y": 0.7749999999999999
+    },
+    {
+     "x": 3.334,
+     "z": -10,
+     "y": 1.1593266739736605
+    },
+    {
+     "x": 4.001,
+     "z": -10,
+     "y": 1.3
+    },
+    {
+     "x": 4.668,
+     "z": -10,
+     "y": 1.1593266739736605
+    },
+    {
+     "x": 5.335,
+     "z": -10,
+     "y": 0.7749999999999999
+    },
+    {
+     "x": 6.002000000000001,
+     "z": -10,
+     "y": 0.2500000000000001
+    }
+   ]
+  },
+  {
+   "id": "sq",
+   "name": "Square Bar",
+   "kind": "ledge",
+   "profile": "square",
+   "pts": [
+    {
+     "x": -16,
+     "z": -6,
+     "y": 0.4
+    },
+    {
+     "x": -13,
+     "z": -6,
+     "y": 0.4
+    }
+   ]
+  }
+ ],
+ "gaps": [
+  {
+   "id": "g1",
+   "name": "OVER THE DEEP END",
+   "x": -11,
+   "z": 0,
+   "r": 2.4
+  }
+ ],
+ "letters": [],
+ "zones": [],
+ "decals": [],
+ "props": [
+  {
+   "id": "w1",
+   "src": "builtin:picnic",
+   "x": -18,
+   "z": -12,
+   "rot": 0.4,
+   "scale": 1
+  },
+  {
+   "id": "w2",
+   "src": "builtin:floodlight",
+   "x": 20,
+   "z": 12,
+   "rot": 0,
+   "scale": 1
+  },
+  {
+   "id": "w3",
+   "src": "builtin:fence",
+   "x": 0,
+   "z": -15.5,
+   "rot": 0,
+   "scale": 1
+  },
+  {
+   "id": "w4",
+   "src": "builtin:bleachers",
+   "x": -20,
+   "z": 4,
+   "rot": 1.5708,
+   "scale": 1
+  }
+ ]
+}
\ No newline at end of file