Sudoku

The Sudoku is generated and can be solved by the Backtracking-algorithm.
You have to fill in numbers, so that "the same single integer may not appear twice in the same 9×9 playing board row or column or in any of the nine 3×3 subregions of the 9×9 playing board."(wikipedia.org)
The design of the numbers, the playing board, the red selection square an the messages were made by Gevater_Tod4711

You can controll the red square with the mouse or the arrow keys. Type in the number you want to insert. You can remove numbers with backspace.