*-----------*
|...|7..|...|
|.3.|..2|..4|
|7.8|4.1|...|
|---+---+---|
|3..|1.5|6..|
|.19|.2.|54.|
|..5|8.3|..2|
|---+---+---|
|...|2.9|1.6|
|9..|3..|.8.|
|...|..8|...|
*-----------*