309.--THE FORTY-NINE COUNTERS.

From Amusements in Mathematics by Henry Ernest Dudeney.

[Illustration]

Can you rearrange the above forty-nine counters in a square so that no letter, and also no number, shall be in line with a similar one, vertically, horizontally, or diagonally? Here I, of course, mean in the lines parallel with the diagonals, in the chessboard sense.

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309.--THE FORTY-NINE COUNTERS.: Amusements in Mathematics by Henry Ernest Dudeney | amphi