*-----------*
|4..|..2|8..|
|..7|.41|..9|
|63.|...|.5.|
|---+---+---|
|...|..9|6.1|
|...|.3.|...|
|9.6|7..|...|
|---+---+---|
|.2.|...|.68|
|8..|27.|4..|
|..3|1..|..5|
*-----------*