                                   
                                   
               ffffffffffffffffffff
               f777777777777777777f
               f7ffffffffffffffff7f
               f7f0ffffffffffffff7f
               f7ff0fffffffffffff7f
               f7f0ff00ffffffffff7f
               f7ffffffffffffffff7f
               f8ffffffffffffffff8f
               f8ffffffffffffffff8f
               f888888888888888888f
               f88888888888888fff8f
               f888888888888888888f
               ffffffffffffffffffff