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