*-----------*
|..3|.18|...|
|27.|6..|...|
|96.|...|1..|
|---+---+---|
|457|.9.|...|
|1..|4.5|..7|
|...|.7.|254|
|---+---+---|
|..4|...|.79|
|...|..2|.61|
|...|73.|4..|
*-----------*