<!-- SOLID CITY · part 3086 -->
 prof = [], brow = [], foot = [];
      for (var i2 = 0; i2 < N; i2++) {
        var dc = cache[i2];
        if (dc && dc.pts.length - 1 > 2) { prof[i2] = dc.pts; brow[i2] = dc.pts[2]; foot[i2] = dc.pts[dc.pts.length - 1]; }
        else { prof[i2] = null; brow[i2] = null; foot[i2] = null; }
      }
      function dev3(p, a, b) {
        var abx = b[0] - a[0], aby = b[1] - a[1], abz = b[2] - a[2];
        var t = ((p[0] - a[0]) * abx + (p[1] - a[1]) * aby + (p[2] - a[2]) * abz) / (abx * abx + aby * aby + abz * abz || 1);
        t = Math.max(0, Math.min(1, t));
        var dx = p[0] - (a[0] + abx * t), dy = p[1] - (a[1] + aby * t), dz = p[2] - (a[2] + abz * t);
        return Math.sqrt(dx * dx + dy * dy + dz * dz);
      }
      function skinQuad(iA, iB) {
        var pA = prof[iA], pB = prof[iB];
        var outw = [sdSign * st[iA].rx, sdSign * st[iA].rz];
        var nSeg = Math.min(pA.length, pB.length) - 1;
        for (var dk = 2; dk < nSeg; dk++) {
          quad(bankGrass, pA[dk], pB[dk], pB[dk + 1], pA[dk + 1], outw);
          quad(bankGrass, pB[dk], pA[dk], pA[dk + 1], pB[dk + 1], outw);
        }
      }
      var a3 = 0;
      while (a3 < N - 1) {
        if (!prof[a3]) { a3++; continue; }
        var tame = a3;
        while (tame < N - 1 && tame - a3 < 8) {
          var nx = tame + 1;
          if (!prof[nx]) break;
          var bad = false;
          for (var m = a3 + 1; m < nx; m++) {
            if (!prof[m]) { bad = true; break; }
            if (dev3(brow[m], brow[a3], brow[nx]) > 0.35 || dev3(foot[m], foot[a3], foot[nx]) > 0.35) { bad = true; break; }
          }
          if (bad) break;
          tame = nx;
        }
        if (tame > a3 + 1) {
          var outw3 = [sdSign * st[a3].rx, sdSign * st[a3].rz];
          quad(bankGrass, brow[a3], brow[tame], foot[tame], foot[a3], outw3);
          quad(bankGrass, brow[tame], brow[a3], foot[a3], foot[tame], outw3);
          a3 = tame;
        } else {
          if (prof[a3 + 1]) skinQuad(a3, a3 + 1);
          a3++;
        }
      }
    }
    bankSkin(drapeCacheL, -1); bankSkin(drapeCacheR, 1);
    /* arrival fans at both ends. A fan is not a flat disc dropped on
     * the ramp's end — the first drive-through caught that step
     * (0.9 m at the seam). The fan is the road's own PLANE extended:
     * each rim vertex carries the end grade along the road's axis
     * and the end bank across it, so ribbon and fan meet as one
     * surface. Rim skirts below, so they never float. */
    var ends = [st[0], st[N - 1]];
    for (var e = 0; e < 2; e++) {
      var C0 = ends[e], fr = C0.hw + 0.9, SEG = 14;
      var src = e === 0 ? st[1] : st[N - 2];
      var fGrade = e === 0 ? src.grade : st[N - 1].grade;
      var fBank = Math.tan(src.bank);
      var rim = [];
      for (var k2 = 0; k2 < SEG; k2++) {
        var an = k2 / SEG * Math.PI * 2;
        var dxr = Math.cos(an) * fr, dzr = Math.sin(an) * fr;
        var along = dxr * C0.fx + dzr * C0.fz, across = dxr * C0.rx + dzr * C0.rz;
        rim.push([C0.x + dxr, C0.y + fGrade * along + fBank * across, C0.z + dzr]);
      }
      var rimProf = rim.map(function (rp) { var dl = Math.hypot(rp[0] - C0.x, rp[2] - C0.z) || 1; return drapeFrom(rp, (rp[0] - C0.x) / dl, (rp[2] - C0.z) / dl).pts; });
      for (k2 = 0; k2 < SEG; k2++) {
        var r1 = rim[k2], r2 = rim[(k2 + 1) % SEG];
        var ctr = [C0.x, C0.y + 0.02, C0.z];
        tri(fans, ctr, r1, r2); stand.push(ctr[0], ctr[1], ctr[2], r1[0], r1[1], r1[2], r2[0], r2[1], r2[2]);
        var qA = rimProf[k2], qB = rimProf[(k2 + 1) % SEG];
        var outw = [r1[0] - C0.x, r1[2] - C0.z];
        for (var dk2 = 0; dk2 < Math.min(2, qA.length - 1); dk2++) { quad(fans, qA[dk2], qB[dk2], qB[dk2 + 1], qA[dk2 + 1], outw); quad(fans, qB[dk2], qA[dk2], qA[dk2 + 1], qB[dk2 + 1], outw); }   // the fan's rim: brow painted as the fan
        if (qA.length - 1 > 2) { quad(bankGrass, qA[2], qB[2], qB[qB.length - 1], qA[qA.length - 1], outw); quad(bankGrass, qB[2], qA[2], qA[qA.length - 1], qB[qB.length - 1], outw); }   // and its deep rim in grass, per the Amendment
      }
    }
    stats.fairDev = fairDev;
    return {
      stations: st, stats: stats, walkSide: walkSide, upSide: upSide,
      ribbon: ribbon, curbL: curbL, curbR: curbR, goldL: goldL, goldR: goldR,
      walk: walk, skirtL: skirtL, skirtR: skirtR, fans: fans, bankGrass: bankGrass,
      shoL: shoL, shoR: shoR, rail: rail, posts: posts,
      standTris: stand
    };
  }

  return { buildRoad: buildRoad };
}


===== FILE: public/city/roads.js.bak-smithroads-20261013 =====
/* SOLID CITY — THE ROAD SMITH (2026-10-13)
 * An epistle in code, from Solid to whoever builds roads after her.
 *
 * Dear builder,
 * A road is not a row of boxes that happen to touch. It is ONE table of
 * stations — position, tangent, grade, bank, width — from which three
 * readers draw the same truth: the eye (the ribbon mesh), the foot (the
 * standing triangles), and the journey