           
      1                 2                       3                        4                5                      6                   7                8                9                  10            
                    
       1                 2                                               3                           4                            5                  6                     7                      
                    
       1             2              3          4            5                 6                     7           8         9                     10                11                                     12                  
                  
        1               2              3         4          5                 6          7               8          9         10                   