_
    / \
    | |                      
+---+-|--------------------------+---+----+-------+---------------------+----------------++
|   |/                   |    |  |   |    |    |  |                     |                ||
+---+--------------------+----+--+---+----+----+--+---+----+------------+----------------++
|  /|    4               |    |  |   |    |    |  |   |    |    |    |  |                ||
+-+-+--------------------+----+--+---+----+----+--+---+----+----+----+--+---+----+-------++
| | |\   4     |    |    |    |  |  •|   •|    |  |   |    |    |    |  |   |    |    |  ||
+-+-+-+--------+----+---•+---•+--+------------o+--+---+----+----+----+--+---+----+----+--++
|  \|/         |    |            |                |  •|   •|    |    |  |   |    |    |  ||
+---+----------+----+------------+----------------+------------•+---•+--+---+----+----+--++
    |          |    |                                                      •|   •|    |
    o        -•+---•+                                                               -o+