public Set<Integer> getTailsAndBody() {
      Set<Integer> nodes = new HashSet<>();
      IntIterator it = myBlockBody.iterator();
      while (it.hasNext()) {
        nodes.add(it.nextInt());
      }
      it = myTails.iterator();
      while (it.hasNext()) {
        nodes.add(it.nextInt());
      }
      return nodes;
    }
public Set<Integer> getTailsAndBody()