.

                                       L
                              o      o  v       o
                           v         e   L         v
                         e             o               e
                        L              v                L
 ­                      o               e                  o
                       v               L                  v
                       e           o        v             e
                       L           e        L            L
                         o           o     v            o
                           v             e             v
                               e         L         e
                                          o
                    ­                      v
                                         ­ e