Nearly everybody knows that a "magic square" is an arrangement of
numbers in the form of a square so that every row, every column, and
each of the two long diagonals adds up alike. For example, you would
find little difficulty in merely placing a different number in each of
the nine cells in the illustration so that the rows, columns, and
diagonals shall all add up 15. And at your first attempt you will
probably find that you have an 8 in one of the corners. The puzzle is to
construct the magic square, under the same conditions, with the 8 in the
position shown.
[Illustration]