Claude-Gaspard Bachet de Méziriac was a great inventor of mathematical games and puzzles. In his landmark work Problèmes plaisants et délectables, he displayed an abiding passion for arithmetic. Several of its problems involve guessing one or more numbers someone has thought of; others use playing cards selected in secret by a player. The book also contains problems about pouring liquids between vessels, crossings, weights and coins, and even a rule for constructing odd-order magic squares. But Bachet was more than an arithmetician. He left us countless recreational-mathematics "tricks," including this highly visual method for constructing magic squares. The illustration opposite speaks for itself.
Constructing an odd-order magic square.
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A theorem must be proved!
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