Score: 15

7 1 7  
4 6 3 2
5 2 1 4
6 7 5 3

Score: 15

    7 2  
3 4 6 5 7
6 1 2 3 1
  5 4 7  

Score: 15

      7
6 7 5 3
5 4 1 2
2 6 3 4
7 1    

Score: 15

  1 4  
7 3 2 5
6 5 1 7
3 4 6  
  7 2  

Score: 15

6 1 4    
2 7 6 3 1
3 4 5 7  
5 2 1