*-----------*
|2..|4..|...|
|..7|56.|.9.|
|65.|..2|3.8|
|---+---+---|
|56.|...|2..|
|...|...|...|
|..9|...|.65|
|---+---+---|
|3.1|9..|.84|
|.8.|.34|5..|
|...|..8|..9|
*-----------*