srecord noeq G22MeshMapper_v2(G22Mesh mesh1, G22Mesh mesh2) {
  // import the important classes
  delegate Anchor, Curve to G22Mesh.
  
  // index structures
  
  MultiMap<Int, Anchor> anchorsByArity2;
    
  // MAPPING VARS
  
  // these are in mesh1
  new LinkedHashSet<Curve> curvesToLookAt;
  
  // keys are the anchors from mesh1, values are the anchors from mesh2
  new Map<Anchor> anchorMap;
  
  // keys are the curves from mesh1, values are the curves from mesh2
  new Map<Curve> mappedCurves;
  
  // EXCEPTIONS (e.g. meshes don't match in signature)
  
  // set to the reason why when a mapping is deemed impossible
  settable O rejectedBecause;
  
  bool rejected() { ret rejectedBecause != null; }
  
  // INTERNAL VARS
  
  bool prechecksDone;
  S sig1, sig2;
  
  void searchForMapping {
    prechecks(); if (rejected()) ret;
    
    anchorsByArity2 = multiMapIndex(mesh2.anchors(), a -> a.arity());
    
    Anchor anchor1 = random(mesh1.anchors());
    Anchor anchor2 = random(anchorsByArity2.get(anchor1.arity());
    assignAnchor(anchor1, anchor2);
  }
  
  void assignAnchor(Anchor anchor1, Anchor anchor2) {
    anchorMap.put(anchor1, anchor2);
    curvesToLookAt.addAll(anchor1.curves());
  }
  
  protected void prechecks {
    set prechecksDone;
    sig1 = mesh1.signature();
    sig2 = mesh1.signature();
    if (!eq(sig1, sig2))
      ret with rejectedBecause(G22SignatureMismatch(mesh1, mesh2));
  }
}