.

                                       M
                               o     oo       o
                             o        N           o
                           n          M            n
                          M        o   o           M  
                          o         n   M           o
                          o         o     o           o
                           n        n   M          n
                            M       o   o         M
                              o       n M        o
                                o       o         o
                                    n   o    n
                                          n

.
                              
                                       W
                                i      in      i
                              n       ne        n
                            n          r            n
                            e        W   i         e    
                            r        n     n        r
                            W       e    r       W
                              i        W  i        i
                               n       n n       n
                                 n       e       n
                                   e      r     e
                                      r   !    r

.

                                      Y
                      ­       u      um      u
                          m        my         m
                         m          Y             m
                        y           y   u            y
                        Y         m    m          Y
                         u         y     Y          u
                          m       u    m        m
                           m       m  y        m
                              y         Y          y
                                Y       u        Y
                                    u   M    u

.
                                      me
                              e      me       e
                            m       me        m
                           e          m            e
                          m          e             m
                          e         m   e           e
                         m        m    e          m
                          e         m    e          e
                           m       m   e         m
                            e         m e         e
                              m       m       m
                                         E

.  
                                        M
                                i       ir         i
                             r         ro            r
                            r          M              r
                           o          i   r             o
                          M         r    o           M
                           i          r    M           i
                            r         i     r           r
                              r        r  o          r
                                o        r        o
                                    r            r

.

                                      I
                              I      II      I
                           I         II         I
                         I            I            I
                        I          I     I          I
                        I          I     I          I
                         I         I     I          I
                          I         I   I          I
                           I          I           I
                             I        I         I
                                 I    I     I
                                       I

.
                                        C
                     ­            a    ac     a
                               c       tu        c
                              t          s           t
                             u       C  a          u
                            s        c     t          s
                            C       u     s          C
                            a        C    a         ­ a
                             c         c  t           c
                               t         u           t
                                  u      s       u
                                      s    :    s