static G22Mesh g22cloneMesh(G22Mesh m1) {
  new G22Mesh m2;
  Map<G22Mesh.Anchor> anchorMap = new Map;
  for (a1 : m1.anchors())
    anchorMap.put(a1, m2.newAnchor(a1.pt));
    
  for (c1 : m1.curves())
    m2.addCurve(new G22Mesh.Curve(
      anchorMap.get(c1.start),
      anchorMap.get(c1.end),
      new OnePathWithOrigin(c1.path)));
    
  ret m2;
}