Anyone who wants to put their math skills to the test will find this site holds many formidable challenges. The collection of puzzles tests visitors' knowledge of "geometry, probability, number theory, algebra, calculus, and logic." Each puzzle is accompanied by a page of hints and a fully worked solution. The site's maintainer states that a pre-college math background is usually sufficient, but practiced mathematicians will likely be stumped on occasion. A new puzzle is added roughly once a week.