Iterable<Iterable<Integer>> iterables = ImmutableList.of(iterable0);

    // Test & Verify
    verifyMergeSorted(iterables, iterable0);
  }

  public void testMergeSorted_pyramid() {
    List<Iterable<Integer>> iterables = new LinkedList<>();
    List<Integer> allIntegers = new ArrayList<>();

    // Creates iterators like: {{}, {0}, {0, 1}, {0, 1, 2}, ...}