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