.
                                   V
                           e      e r      e
                         r        b o        r
                       b          s e          b
                      o            V             o
                     s              e               s
                    e               r                 e
                   V               b                  V
                   e             o      s              e
                   r            e        V             r
                    b           e        r             b
                     o            b     o           o
                        s             s            s
                              e       e      e
                                       V
                                       e
                                       r
                                       b
                                       o
                                       s
                                       e