[Illustration]

164.—­THE POTATO PUZZLE.

Take a circular slice of potato, place it on the table, and see into how large a number of pieces you can divide it with six cuts of a knife.  Of course you must not readjust the pieces or pile them after a cut.  What is the greatest number of pieces you can make?

[Illustration: 

--------
/   \ 1/   \
/ \ 2 \/ 3 / \
/   \  /\  /   \
/ \ 4 \/ 5\/ 6 / \
|   \  /\  /\  /   |
\  7\/ 8\/ 9\/10 /
\  /\  /\  /\  /
\/11\/12\/13\/
\  /\  /\  /
\/14\/15\/
\  /\  /
\/16\/
-----

]

The illustration shows how to make sixteen pieces.  This can, of course, be easily beaten.

165.—­THE SEVEN PIGS.

[Illustration]

+------------------------------+
|                              |
|                        P     |
|                              |
|          P                   |
|       P                      |
|           P                  |
|              P               |
|           P                  |
|     P                        |
|                              |
+------------------------------+

Here is a little puzzle that was put to one of the sons of Erin the other day and perplexed him unduly, for it is really quite easy.  It will be seen from the illustration that he was shown a sketch of a square pen containing seven pigs.  He was asked how he would intersect the pen with three straight fences so as to enclose every pig in a separate sty.  In other words, all you have to do is to take your pencil and, with three straight strokes across the square, enclose each pig separately.  Nothing could be simpler.

[Illustration]

The Irishman complained that the pigs would not keep still while he was putting up the fences.  He said that they would all flock together, or one obstinate beast would go into a corner and flock all by himself.  It was pointed out to him that for the purposes of the puzzle the pigs were stationary.  He answered that Irish pigs are not stationery—­they are pork.  Being persuaded to make the attempt, he drew three lines, one of which cut through a pig.  When it was explained that this is not allowed, he protested that a pig was no use until you cut its throat.  “Begorra, if it’s bacon ye want without cutting your pig, it will be all gammon.”  We will not do the Irishman the injustice of suggesting that the miserable pun was intentional.  However, he failed to solve the puzzle.  Can you do it?

166.—­THE LANDOWNER’S FENCES.

The landowner in the illustration is consulting with his bailiff over a rather puzzling little question.  He has a large plan of one of his fields, in which there are eleven trees.  Now, he wants to divide the field into just eleven enclosures by means of straight fences, so that every enclosure shall contain one tree as a shelter for his cattle.  How is he to do it with as few fences as possible?  Take your pencil and draw straight lines across the field until you have marked off the eleven enclosures (and no more), and then see how many fences you require.  Of course the fences may cross one another.