x x x x x x x x x x x x x x x x

x x x x x x x x c c x x x x x x
                ^

x x x x c c x x c c x x x x x x
        ^

x x c c c c x x x x x x x x x x
    ^

c c c c x x x x x x x x x x x x
  ^

x x x x x x x x x x x x x x x x
               |       /

               | /
              s s s

c c s

x x x x x x x x x x x x x x x x
|       |

x x c c x x x x x x x x x x x x
|    ^  |

c c c c x x x x x x x x x x x x
|  ^    |