Swedish programmer, Hans Andersson, used Lego Mindstorms NXT kit to develop a robot that can solve Sudoku Puzzles (Sudoko).

The robot uses an optical sensor to scan the puzzle. First performs a quick scan to determine which cells are empty. There have been empty squares and figures, then the robot moves slowly forward for scanning a new line. Rough and “noisy” image – through the use of robot algorithm Otsu (The Otsu Method) – then converted into sharper black and white image, and the robot determines all the figures recorded in the cells.

After that the robot solves the puzzle and fill in the empty squares. And Use a
Lego Mindstorms processor is too slow to work on a complex mathematical algorithm, and it does not allow recursive operations (returning back to the algorithm). So Andersson, apparently, was forced to seriously optimize the algorithm of this – a model – the robot.