mt2.split(tok(4));
mt2.split(tok(12));
mt2.split(tok(2));
mt2.split(tok(10));
mt2.split(tok(9));
mt2.split(tok(11));
ranges = mt2.invalids(full);
ranges.next().addAll(new HIterator(2)); // (0,2]
ranges.next().addAll(new HIterator(4)); // (2,4]
ranges.next().addAll(new HIterator(6, 8)); // (4,8]: depth 2