*-----------*
|.98|..2|...|
|73.|.8.|.4.|
|4..|..5|...|
|---+---+---|
|...|.9.|.17|
|9.7|...|6.4|
|38.|.1.|...|
|---+---+---|
|...|8..|..5|
|.5.|.4.|.21|
|...|5..|98.|
*-----------*