*-----------*
|...|..6|..7|
|3.8|..5|.9.|
|...|1..|.5.|
|---+---+---|
|4..|93.|...|
|15.|4.7|.39|
|...|.52|..4|
|---+---+---|
|.7.|..3|...|
|.4.|5..|8.1|
|5..|7..|...|
*-----------*