[]      ¤
[]  ¤
[]¤                       ¤                         &&&
[]   §                                            &         &
[]      §                 ()                      &                     $$$
[]         §              ()                         &&&          $         $
                            ()                                 &        $
                             ()                     &        &           $ $ $
                              ()                     &&&&                      $
                                                                            $        $ 
                                                                               $$$