0 <==> 8
1 <==> 7
2 <==> 6
3 <==> 9
4 <==> 5

0 <==> 1
2 <==> 5
3 <==> 8
4 <==> 7
6 <==> 9

1 <==> 6
2 <==> 7
3 <==> 8
4 <==> 9
5 <==> 0