my least favorite sudoku of all time.

This was yesterday's ironsudoku. It was way. too. hard.

*-----------*
|..2|.8.|.5.|
|...|.21|.4.|
|...|5..|7.2|
|---+---+---|
|.75|...|9..|
|.1.|9.3|.7.|
|..9|...|31.|
|---+---+---|
|6.4|..8|...|
|.8.|23.|...|
|.2.|.9.|4..|
*-----------*