+----------------------------------------------+
       |             S1               S2              |
       |              O...............O               |
       |     ......... .......         .              |
       |    .                 .         .             |
       |S3 .                   . S4      . S5         |
 L1----|.O......................O.........O...........|------L4
       |   .                     .         .          |
       |    .                     .         .         |
       |     . S6                  . S7      . S8     |
       |      O     ................O.........O.......|------L7
       |     . .   .                 .   .....        |
       |S9  .   . .S10                . .             |
L2-----|...O.....O.....................O..............|------L8
       |  .                          S11              |
L3-----|..                                            |
       |                                          AN1 |
       +----------------------------------------------+