20
12
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
|                           |               |       |       |       |           |
+---+---+   +---+---+   +---+---+---+   +   +   +   +---+   +   +---+   +---+   +
|       |   |               |       |   |       |           |   |           |   |
+   +---+   +   +   +---+   +   +   +---+   +---+---+---+   +   +   +---+---+   +
|           |   |       |   |   |       |       |       |   |       |           |
+   +---+---+   +   +   +---+   +---+---+---+---+   +---+   +---+---+   +---+---+
|   |           |   |       |               |       |               |       |   |
+   +---+---+   +   +---+   +---+---+---+   +   +---+---+---+---+   +   +   +   +
|           |   |       |                   |                   |   |   |       |
+---+---+   +---+---+   +---+---+---+   +---+---+   +---+---+---+   +   +---+---+
|           |       |               |   |           |   |           |   |       |
+   +---+---+---+   +---+   +---+   +   +---+   +---+   +   +   +---+   +   +   +
|   |   |       |           |       |       |   |           |       |       |   |
+   +   +   +   +---+---+---+---+   +---+   +   +---+---+---+---+   +   +   +   +
|       |   |   |   |           |   |   |   |                       |   |   |   |
+---+   +   +   +   +   +   +---+   +   +   +---+---+---+   +---+---+---+   +   +
|       |   |   |       |   |       |                       |       |   |   |   |
+   +---+   +   +---+---+   +   +---+   +---+---+---+---+   +   +   +   +   +   +
|           |               |   |   |   |   |               |   |   |       |   |
+   +---+---+---+---+---+---+   +   +   +   +   +---+---+---+   +   +   +   +   +
|           |               |       |   |       |       |       |       |   |   |
+   +---+   +---+---+---+   +   +   +   +---+---+---+   +---+   +---+---+---+---+
|   |                   |       |   |                                           |
+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+---+
