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

+