*-----------*
|..2|...|..7|
|81.|.94|...|
|6..|2..|.4.|
|---+---+---|
|45.|...|3..|
|...|.4.|...|
|..9|...|.56|
|---+---+---|
|.3.|..8|..4|
|...|65.|.28|
|9..|...|1..|
*-----------*