12
8
+---+---+---+---+---+---+---+---+---+---+---+---+
|       |               |   |   |               |
+   +---+   +   +   +---+   +   +   +---+---+   +
|           |   |   |   |   |       |       |   |
+   +---+---+---+   +   +   +   +---+   +   +---+
|               |       |       |       |       |
+   +   +   +   +   +---+   +---+   +---+---+   +
|   |   |   |   |       |           |       |   |
+   +---+   +---+---+   +   +---+   +   +---+   +
|   |   |   |       |           |       |   |   |
+   +   +---+   +---+---+---+---+---+---+   +---+
|   |       |                                   |
+   +---+   +   +   +---+---+---+   +---+---+---+
|               |           |                   |
+---+   +---+---+   +---+---+---+   +---+   +   +
|               |           |       |       |   |
+---+---+---+---+---+---+---+---+---+---+---+---+
