.

                                         D
                              e        e a         e
                            a          r D           a
                           r             e               r
                          D          a     r           D
                          e           D    e            e
                           a           a    r           a
                            r           D  e           r
                             D           a            D
                               e          r           e
                                 a        D        a
                                   r       e      r
                                            a
                                            r