8
5
+---+---+---+---+---+---+---+---+
|       |           |       |   |
+   +---+---+   +   +   +   +   +
|       |       |       |       |
+   +   +   +---+---+---+---+   +
|   |       |       |   |   |   |
+   +---+---+   +---+   +   +   +
|                   |       |   |
+---+   +   +---+---+   +---+   +
|       |                   |   |
+---+---+---+---+---+---+---+---+
