private List<Integer> getLongestLayerLine() {
    int len = 0;
    int index = 0;

    Helix helix = helixLayers.getByLargestContacts();
    List<List<Integer>> layerLines = helix.getLayerLines();
    for (int i = 0; i < layerLines.size(); i++) {
      if (layerLines.get(i).size() > len) {
        len = layerLines.get(i).size();
        index = i;
      }
    }
    return layerLines.get(index);
  }