.
                                     F
                              i     i s      i
                           s       h F        s
                          h        is           h
                         F       h     F        F
                         i        i       s         i
                         s        h     F         s
                          h        i    s         h
                            F         h         F
                                i      •      i
               ­                        s
                                       h