256.—­THE DIAMOND PUZZLE.

IN how many different ways may the word DIAMOND be read in the arrangement shown?  You may start wherever you like at a D and go up or down, backwards or forwards, in and out, in any direction you like, so long as you always pass from one letter to another that adjoins it.  How many ways are there?

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257.—­THE DEIFIED PUZZLE.

In how many different ways may the word DEIFIED be read in this arrangement under the same conditions as in the last puzzle, with the addition that you can use any letters twice in the same reading?

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258.—­THE VOTERS’ PUZZLE.

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Here we have, perhaps, the most interesting form of the puzzle.  In how many different ways can you read the political injunction, “RISE TO VOTE, SIR,” under the same conditions as before?  In this case every reading of the palindrome requires the use of the central V as the middle letter.

259.—­HANNAH’S PUZZLE.

A man was in love with a young lady whose Christian name was Hannah.  When he asked her to be his wife she wrote down the letters of her name in this manner:—­

    H H H H H H
    H A A A A H
    H A N N A H
    H A N N A H
    H A A A A H
    H H H H H H

and promised that she would be his if he could tell her correctly in how many different ways it was possible to spell out her name, always passing from one letter to another that was adjacent.  Diagonal steps are here allowed.  Whether she did this merely to tease him or to test his cleverness is not recorded, but it is satisfactory to know that he succeeded.  Would you have been equally successful?  Take your pencil and try.  You may start from any of the H’s and go backwards or forwards and in any direction, so long as all the letters in a spelling are adjoining one another.  How many ways are there, no two exactly alike?

260.—­THE HONEYCOMB PUZZLE.

[Illustration]

Here is a little puzzle with the simplest possible conditions.  Place the point of your pencil on a letter in one of the cells of the honeycomb, and trace out a very familiar proverb by passing always from a cell to one that is contiguous to it.  If you take the right route you will have visited every cell once, and only once.  The puzzle is much easier than it looks.

261.—­THE MONK AND THE BRIDGES.

In this case I give a rough plan of a river with an island and five bridges.  On one side of the river is a monastery, and on the other side is seen a monk in the foreground.  Now, the monk has decided that he will cross every bridge once, and only once, on his return to the monastery.  This is, of course, quite easy to do, but on the way he thought to himself, “I wonder how many different routes there are from which I might have selected.”  Could you have told him?  That is the puzzle.  Take your pencil and trace out a route that will take you once over all the five bridges.  Then trace out a second route, then a third, and see if you can count all the variations.  You will find that the difficulty is twofold:  you have to avoid dropping routes on the one hand and counting the same routes more than once on the other.