+---+---+---+---+---+
|   |   |   |   |   |
+---+---+   +---+---+
|   |   |   |   |   |
+---+---+   +---+---+
|                   |
+---+---+   +---+---+
|   |   |   |   |   |
+---+---+   +---+---+
|   |   |   |   |   |
+---+---+---+---+---+