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