.
                                      m
                       ­       o      or       o
                            r        on          r
            ­               o         m            o
                           n        o  r           n
                           m      o    n         m
                            o      m   o         o
                              r      r   o        r
                                o    n m      o
                                  n    o      n
        ­                                 r
                                         o
                                         n