37                                                     38                                                  39                                                      40

               61                                                          62                                                 63                                                      64

               65                                                      66                                                    67                                                    68

               57                                                      58                                                  59                                                      60

               45                                                       46                                                 47                                                          48

               69                                                      70                                                    71                                                         72

                            1                                                         2                                                       3                                                           4

               17                                                     18                                                    19                                                        20

               29                                                    30                                                     31                                                       32

                5                                                       6                                                        7                                                        8

               13                                                       14                                                  15                                                     16

               41                                                     42                                                   43                                                      44

               33                                                      34                                                   35                                                     36

               21                                                     22                                                  23                                                         24

               77                                                      78                                                     79                                                    80

               73                                                       74                                                      75                                                   76

                25                                                      26                                                   27                                                        28

               49                                                       50                                                 51                                                      52

               9                                                        10                                                   11                                                           12

               53                                                              54                                         55                                                      56