0 1 2 3 4 5 6 7 8 9 [0..9]
[]
0 3 6 9 [0 3 6 9]
9 6 3 0 [9 6 3 0]
0 [0]
0 [0]
1 3 5 7 9 [1 3 5 7 9]
0 0 [0 0]
