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  1. Math

    A Magic Knight’s Tour

    For as long as chessboards have existed, there have been puzzles involving chessboards and chess pieces. Some of the most enduring conundrums involve knights. Example of a knight’s tour in which the rows and columns have the same sum (260), but the diagonals add up to 348 and 168. According to the rules of chess, […]

    By Ivars Peterson
  2. Math

    The Bias of Random-Number Generators

    Some popular random-number generators fail even in simulating a coin toss.

    By Ivars Peterson
  3. Math

    Rolling with Reuleaux

    Have you ever wondered why the cover of a manhole is nearly always round? Why isn’t it oval or square? Reuleaux curve based on an equilateral triangle.