Perhaps inevitably, sudoku puzzles are showing up in the mathematics classroom. Although these extremely popular puzzles don't involve even arithmetic, they're wonderful exercises in logic—and lend themselves to illuminating excursions into such mathematical topics as combinatorics, Latin squares, polyominoes, computer algorithms, chess problems, graph colorings, and permutation group theory.
This year's Joint Mathematics Meetings (JMM) in New Orleans provided evidence of this interest in the form of a two-part session devoted to sudoku and other puzzles, organized by Laura Taalman of James Madison University.
Although Taalman has described sudoku as "muggle math," she finds the puzzles endlessly fascinating and has created entertaining sudoku variants. In "snowflake" sudoku, for example, the numbers from 1 to 9 are filled in so that no number is repeated in any row, column, block, or various diagonals. In color variants, the usual sudoku rules apply, but no numbe