<!-- SOLID CITY · part 3154 -->
ed = false; g2.add(back);
    var mat = textPlate(lines, w, h, fs);
    var f1 = new T.Mesh(new T.PlaneGeometry(w, h), mat); f1.position.z = 0.14; f1.frustumCulled = false; g2.add(f1);
    var f2 = new T.Mesh(new T.PlaneGeometry(w, h), mat); f2.position.z = -0.14; f2.rotation.y = Math.PI; f2.frustumCulled = false; g2.add(f2);
    footprints.push({ x: x, z: z, w: w + 0.6, d: 0.8, a: ry, y0: y - h / 2 - 0.3, y1: y + h / 2 + 0.3 });
    return g2;
  }
  function lamp(x, y, z, s) {
    cyl(solid, 0.09, 0.13, 3.4 * (s || 1), 6, mat4(x, y + 1.7 * (s || 1), z, 0, 0, 0), C.titanium);
    sph(glow, 0.34 * (s || 1), mat4(x, y + 3.55 * (s || 1), z, 0, 0, 0), C.lamp);
  }
  function tree(x, y, z, s) {
    cyl(solid, 0.55, 0.7, 0.8, 8, mat4(x, y + 0.4, z, 0, 0, 0), C.marbleRed);
    cyl(solid, 0.13 * s, 0.2 * s, 2.2 * s, 6, mat4(x, y + 0.8 + 1.1 * s, z, 0, 0, 0), C.trunk);
    sph(solid, 1.9 * s, mat4(x, y + 0.8 + 2.6 * s, z, 0, 0, 0, 1, 0.85, 1), C.leaf);
    sph(solid, 1.25 * s, mat4(x + 0.9 * s, y + 0.8 + 2.1 * s, z + 0.5 * s, 0, 0, 0), C.leafLight);
    footprints.push({ x: x, z: z, w: 1.5, d: 1.5, a: 0, y0: y, y1: y + 1 });
  }
  /* a dwelling in the marble language: stone base, gold-lit
   * door, a lanai toward the plaza */
  function frameOf(r, a, cx, cz) {
    var px = cx + Math.cos(a) * r, pz = cz + Math.sin(a) * r;
    return { x: px, z: pz, tx: -Math.sin(a), tz: Math.cos(a), rx: Math.cos(a), rz: Math.sin(a), a: a };
  }
  function house(fr, y, s, floors) {
    var M = mat4(fr.x, y, fr.z, 0, Math.atan2(fr.tx, fr.tz), 0);
    function L(lx, ly, lz) { return mat4(fr.x + fr.tx * lx + fr.rx * lz, y + ly, fr.z + fr.tz * lx + fr.rz * lz, 0, Math.atan2(fr.tx, fr.tz), 0); }
    var W = 9 * s, D = 7.5 * s, Hh = 3.4 * s * floors;
    box(solid, W, Hh, D, (function () { var m = L(0, Hh / 2, 0); return m; })(), C.stone);
    box(solid, W + 1.2 * s, 0.5 * s, D + 1.2 * s, L(0, Hh + 0.25 * s, 0), C.stoneDark);
    if (floors > 1) box(solid, W * 0.7, 0.4 * s, D * 0.7, L(0, Hh + 0.7 * s, 0), C.roof);
    box(glow, 1.3 * s, 2.3 * s, 0.18, L(0, 1.15 * s, -D / 2 - 0.06), C.door);
    box(solid, W * 0.66, 0.22 * s, 2.6 * s, L(0, 0.11 * s, -D / 2 - 1.6 * s), C.stoneDark);
    [-1, 1].forEach(function (sgn) { box(glow, 1.1 * s, 1 * s, 0.14, L(sgn * W * 0.3, 1.9 * s, -D / 2 - 0.05), C.win); });
    if (floors > 1) [-1, 1].forEach(function (sgn) { box(glow, 1.1 * s, 1 * s, 0.14, L(sgn * W * 0.28, Hh - 1.1 * s, -D / 2 - 0.05), C.win); });
    footprints.push({ x: fr.x, z: fr.z, w: W + 0.6, d: D + 3.4 * s, a: Math.atan2(fr.tx, fr.tz), y0: y, y1: y + Hh + 1 });
    return M;
  }
  function stall(fr, y, tint) {
    function L(lx, ly, lz) { return mat4(fr.x + fr.tx * lx + fr.rx * lz, y + ly, fr.z + fr.tz * lx + fr.rz * lz, 0, Math.atan2(fr.tx, fr.tz), 0); }
    box(solid, 3.4, 1.05, 1.1, L(0, 0.52, 0), C.stoneDark);
    [-1.5, 1.5].forEach(function (lx) { box(solid, 0.14, 2.5, 0.14, L(lx, 1.25, -0.4), C.trunk); });
    box(solid, 4.1, 0.14, 2.2, L(0, 2.55, 0.1), tint);
    for (var i = 0; i < 3; i++) sph(glow, 0.3, L(-1 + i, 1.25, 0), i % 2 ? C.vialG : C.lamp);
    footprints.push({ x: fr.x, z: fr.z, w: 4, d: 2.4, a: Math.atan2(fr.tx, fr.tz), y0: y, y1: y + 2.2 });
  }
  /* formations of the deep: stalactites above, stalagmites below */
  function formation(x, y, z, s, hang) {
    if (hang) cone(solid, 0.9 * s, 3.8 * s, 7, mat4(x, y - 1.9 * s, z, Math.PI, 0, 0), C.basalt);
    else cone(solid, 1.0 * s, 3.0 * s, 7, mat4(x, y + 1.5 * s, z, 0, 0, 0), C.basalt);
    cone(solid, 0.5 * s, 1.8 * s, 6, mat4(x + 0.8 * s, hang ? y - 0.9 * s : y + 0.9 * s, z + 0.4 * s, hang ? Math.PI : 0, 0, 0), C.marbleRed);
  }
  var layers = [];   // {cx, cz, rIn, rOut, y} standable ring terraces
  var crystals = [];

  function contourR(cx, cz, a, yTarget) {
    for (var r = 138; r < 212; r += 3) { if (H(cx + Math.cos(a) * r, cz + Math.sin(a) * r) > yTarget) return r; }
    return 212;
  }
  function buildCity(Cc, big) {
    var F = Cc.f, cx = Cc.x, cz = Cc.z;
    marbleDisc(cx, F, cz, 32, marbleBlack, 4);
    cyl(glow, 32.6, 32.6, 0.18, 40, mat4(cx, F + 0.3, cz, 0, 0, 0), C.gold);
    cyl(solid, 47, 47, 0.14, 44, mat4(cx, F + 0.07, cz, 0, 0, 0), C.stoneDark);   // ring road
    /* the lava cloth hung on the hollow's wall (Plate I) —
     * and when the image has been rayscanned, the skirt is
     * BAKED OUT OF THE IMAGE ITSELF: folded concave and
     * convex, crystallized, and given collision, so the
     * folded wall is a wall in law as well as in looks */
    if (lavaTex) {
      var hiG = opts.texTier !== 'lo';
      var skirtGeo = new T.CylinderGeometry(149.5, 141.2, 58, hiG ? 168 : 80, hiG ? 12 : 6, true);
      if (HEIGHT) displace(skirtGeo, 12, 2, 1.0);
      var skirt = new T.Mesh(skirtGeo, lavaMat(12, 2, T.BackSide, !!HEIGHT));
      skirt.position.set(cx, F + 21, cz); skirt.name = 'lava-skirt'; skirt.frustumCulled = false; group.add(skirt);
      if (HEIGHT) for (var sa = 0; sa < Math.PI * 2; sa += Math.PI / 18) {