10, 20, 30, 40, 50, 60, 70
50 | --------+-------- | | 20 70 -----+----- -----+ | | | 10 40 60 -----+ | 30
50, 20, 10, 40, 30, 70, 60
50 | --------+-------- | | 20 70 -----+----- -----+ | | | 10 40 60 -----+ | 30
10, 30, 40, 20, 60, 70, 50
50 | --------+-------- | | 20 70 -----+----- -----+ | | | 10 40 60 -----+ | 30