*-----------*
|.1.|.7.|43.|
|..8|...|...|
|2..|.3.|5.1|
|---+---+---|
|1.3|..4|7.5|
|75.|9.3|.48|
|9.2|7..|6.3|
|---+---+---|
|8.5|.4.|..9|
|...|...|3..|
|.91|.5.|.2.|
*-----------*