.
                                    C
                           r      a s       r
                        a         h S           a
                       s             i               s
                      h            t   e            h
                     S            C     r            S
                      i            a     s            i
                       t            h   S            t
                         e          i   t            e
                           C        e  C         C
                               r       r      r
                                        A
                                        S
                                        H