.

                                 N
                         e     ev       e
                     v         er           v
                    e           N             e
                   r           e   v            r
                   N         e     r           N
                   e          N    e           e
                    v          v   e           v
                      e           r             e
                        r         N          r
                          N       e       N
                              e    V    e
                                    E
                                    R