.
                                    
                                     S
                            c      c  r       c
                        r          e  a           r
                      e              m               e
                     a               s                  a
                    m              c                   m
                    s              r   e                 s
                    c              a  m                c
                      r             s  c                r
                        e           r e               e
                          a          m            a
                              m              m