o
                                         ˉ    ˉoo
                                       /         oo \o
                                     /       oooo   \
                                          oooooo
                                  o     ooooooo
                                oo    ooooooooo        
                             ooo     oooooooooooo
                           oooooo oooooooooooooooo
                           ooooooooooooooooooooooo