+-----------+   +-----------+    +-----------+
|     .     |   |           |    |      .    |
|     x     |   |           |    |     .     |
|     x     |   |           |    |    .      |
|     .     |   |.xx . x .  |    |   x       |
|     .     |   |           |    |  x        |
|     x     |   |           |    | x         |
+-----------+   +-----------+    +-----------+