World’s Toughest Sudoku

According to DailyMail in August 2010, linked here is the world’s toughest sudoku at the time.

It was created by Dr. Arto Inkala, an environmental scientist with a doctorate in applied mathematics. It was generated by a computer program that he devised. The puzzle has only one solution and can take someone 3 days to solve by logic.

The article says

“So its difficulty – and frustration factor – lies in the number of mental leaps needed to complete each square.

Like chess, those trying to solve it will have to think several moves ahead. Many exasperating deadends have also been built in.”

The solution is linked here.

You can play sudoku online here.


Mah-Jongg Solitaire Game

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This game was programmed by Thomas Weibel using DHTML and Javascript. The object of the game is to remove tiles that are “open” on the left and the right. Don’t worry, if you can’t see any open tiles, there is a “hint” button that may reveal moves that you did not see. There is also a “zoom” button if you find the tiles to be too small and is straining your eyes. Note that not all games can be won. However, good players can sometimes win one out of every three games.

Classic Reversi Game

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This is the classic game of Othello where you play against a computer opponent. Consisting of black and white stones, you place your color stone on the board causing the opponents color stone to flip to your color. Whoever has the most colored stones at the end wins. What is interesting about this game is that it has unlimited undos.