-------------------------------------
|     4   2 |     5     | 9       8 |
|   +   +   +   +   +   +   +   +   |
|     7     |           |           |
|   +   +   +   +   +   +   +   +   |
| 5         |         9 | 3         |
|---+---+---+---+---+---+---+---+---|
|     2     |     4     | 5         |
|   +   +   +   +   +   +   +   +   |
|           |     3     |           |
|   +   +   +   +   +   +   +   +   |
|           |           |         2 |
|---+---+---+---+---+---+---+---+---|
|           |         3 |     7     |
|   +   +   +   +   +   +   +   +   |
| 8         |           | 6       9 |
|   +   +   +   +   +   +   +   +   |
|         9 | 1       7 |     8     |
-------------------------------------

          DIFFICULTY: 1.75