This is a presentation of 12 coin problem

1. 9 10 11 12
1 2 4 5 8
3 6 7

2. 9 10
11 12
1 2 3 4
5 6 7 8

3. 9 10 11 12
1 3 4
2
5 6 7 8

4. 9
11 4 12 8
6 10 2 3
1 7 5

5. 9
11 6 4
10
12 2 3 8
1 7 5

6. 9
12 2 3 8
11 10 4
6
1 7 5