*-----------*
|9..|...|7..|
|..1|6.4|...|
|543|9.2|...|
|---+---+---|
|.5.|..7|4..|
|72.|...|.35|
|..6|5..|.9.|
|---+---+---|
|...|4.9|586|
|...|2.5|9..|
|..5|...|..2|
*-----------*