167.--THE WIZARD'S CATS.

[Illustration]

A wizard placed ten cats inside a magic circle as shown in our

illustration, and hypnotized them so that they should remain stationary

during his pleasure. He then proposed to draw three circles inside the

large one, so that no cat could approach another cat without crossing a

magic circle. Try to draw the three circles so that every cat has its

own enclosure and cannot reach another cat without crossing a line.

Amusements in Mathematics · 第 195 / 970 题