1 2: 1 2
1 3: 1 2 3
1 3: 1 3
1 4: 1 2 3 4
1 4: 1 3 4
2 1: 2 1
2 1: 2 3 4 1
2 3: 2 1 3
2 3: 2 3
2 4: 2 1 3 4
2 4: 2 3 4
3 1: 3 4 1
3 2: 3 4 1 2
3 4: 3 4
4 1: 4 1
4 2: 4 1 2
4 3: 4 1 2 3
4 3: 4 1 3