public override int GetHashCode()
 {
     return(_parent.GetHashCode() ^ _index);
 }
 public override int GetHashCode()
 {
     return(_parent.GetHashCode() ^ _side.GetHashCode());
 }
 public override int GetHashCode()
 {
     return(_parent.GetHashCode() ^ _index ^ (_baseFace.GetHashCode() << 30));
 }