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