.
                                     D
                             e     e l       e
                           l        i  c         l
                         c         ou           c
                        o           s             o
                        u        D  e           u
                         s       l      i          s
                          D      c    o      ­  D
                            e      u s         e
                              l      ~        l
               ­                       i
                                      c