*-----------*
|.9.|.7.|...|
|..6|4..|..8|
|43.|...|..6|
|---+---+---|
|35.|12.|...|
|...|6.7|...|
|...|.48|.52|
|---+---+---|
|8..|...|.91|
|7..|..5|6..|
|...|.3.|.2.|
*-----------*