[Illustration]
This illustration represents a troupe of clowns I once saw on the
Continent. Each clown bore one of the numbers 1 to 9 on his body. After
going through the usual tumbling, juggling, and other antics, they
generally concluded with a few curious little numerical tricks, one of
which was the rapid formation of a number of magic squares. It occurred
to me that if clown No. 1 failed to appear (as happens in the
illustration), this last item of their performance might not be so easy.
The reader is asked to discover how these eight clowns may arrange
themselves in the form of a square (one place being vacant), so that
every one of the three columns, three rows, and each of the two diagonals
shall add up the same. The vacant place may be at any part of the square,
but it is No. 1 that must be absent.