*-----------*
|2..|...|..6|
|.76|...|41.|
|...|7.4|5..|
|---+---+---|
|9.7|3..|..4|
|.2.|.7.|.6.|
|6..|..8|9.7|
|---+---+---|
|..3|2.5|...|
|.12|...|74.|
|4..|...|..5|
*-----------*