Sudoku   

The objective is to fill the grid.

The same single item may not appear twice in the same row or column or in any of the nine sub-grids (3x3)

Your highscore will be saved (only for registered users).
Each Thursday, at 00:00 (localtime), for each level, the best player of the week wins 60 ct$. A player is allowed to win only one time per game.

Good luck!