*-----------*
|7..|..3|...|
|..1|..6|5.9|
|...|.1.|.4.|
|---+---+---|
|.76|..9|...|
|5.4|.3.|9.7|
|...|7..|82.|
|---+---+---|
|.1.|.8.|...|
|6.9|2..|1..|
|...|6..|..2|
*-----------*