// Returns true if at least one face matches the facesel rule but all of them
public bool FaceSelectionIsValid(ConwayPoly.FaceSelections facesel)
{
if (ConwayOperators.Count == 0 && PolyType > 0)
{
_conwayPoly = new ConwayPoly(WythoffPoly); // We need a conway poly
}
int includedFaceCount = Enumerable.Range(0, _conwayPoly.Faces.Count).Count(x => _conwayPoly.IncludeFace(x, facesel));
return(includedFaceCount > 0 && includedFaceCount < _conwayPoly.Faces.Count);
}