----------------------------------
       |                                  |
       |                2                 |
       |                                  |
       |      1                           |
       |                          3       |
       |                                  |
       |                                  |
       |    7                       4     |
       |                                  |
       |                                  |
       |                 6     5          |
       |                                  |
        ----------------------------------