## Links

#### Problems and Puzzles

A collection of websites containing problems and puzzles of varying difficulty. Some are purely mathematical, others are of a recreational nature. Be warned that many of the mathematical problems would be considered "4 Star".

#### Mathematical

- Nick's Puzzles range over geometry, probability, number theory, algebra, calculus, and logic. Problems and solutions are presented clearly and provide an excellent challenge.

http://www.qbyte.org/puzzles/ - Macalester College Problem of the Week, hosted by the Math Forum.

http://mathforum.org/wagon/ - Purdue University Problem of the Week.

http://www.math.purdue.edu/pow/ - Canadian Mathematics Competition.

http://cemc.math.uwaterloo.ca/contests/contests.html - The International Mathematical Olympiad's official website.

http://www.imo-official.org/

#### Recreational

*wu :: riddles*, created by William Wu, contains a massive collection of riddles and puzzles. Although solutions are not published, there is a forum where problems can be discussed.

http://www.ocf.berkeley.edu/~wwu/riddles/intro.shtml- For the definitive guide to dissection problems I would refer you to Stewart Coffin's amazing,
*The Puzzling World of Polyhedral Dissections*.

http://www.johnrausch.com/PuzzlingWorld/ - The rec.puzzles archive is an immense collection of categorised puzzles taken from years of newgroup puzzle discussions.

http://rec-puzzles.org/ - The Grey Labyrinth is a superbly produced and presented website, containing a vast collection of puzzles of a lateral and perplexing nature.

http://www.greylabyrinth.com/ - Although a little ambitious in its name, 'The Ultimate Puzzle Site!' provides a good mixture of challenging problems of varying difficulty.

http://www.dse.nl/puzzle/index_us.html