157.--THE TABLE-TOP AND STOOLS.

[Illustration]

One object that I had in view when presenting this little puzzle was to

point out the uncertainty of the meaning conveyed by the word "oval."

Though originally derived from the Latin word _ovum_, an egg, yet what

we understand as the egg-shape (with one end smaller than the other) is

only one of many forms of the oval; while some eggs are spherical in

shape, and a sphere or circle is most certainly not an oval. If we speak

of an ellipse--a conical ellipse--we are on safer ground, but here we

must be careful of error. I recollect a Liverpool town councillor, many

years ago, whose ignorance of the poultry-yard led him to substitute the

word "hen" for "fowl," remarking, "We must remember, gentlemen, that

although every cock is a hen, every hen is not a cock!" Similarly, we

must always note that although every ellipse is an oval, every oval is

not an ellipse. It is correct to say that an oval is an oblong

curvilinear figure, having two unequal diameters, and bounded by a curve

line returning into itself; and this includes the ellipse, but all other

figures which in any way approach towards the form of an oval without

necessarily having the properties above described are included in the

term "oval." Thus the following solution that I give to our puzzle

involves the pointed "oval," known among architects as the "vesica

piscis."

[Illustration: THE TWO STOOLS.]

The dotted lines in the table are given for greater clearness, the cuts

being made along the other lines. It will be seen that the eight pieces

form two stools of exactly the same size and shape with similar

hand-holes. These holes are a trifle longer than those in the

schoolmaster's stools, but they are much narrower and of considerably

smaller area. Of course 5 and 6 can be cut out in one piece--also 7 and

8--making only _six pieces_ in all. But I wished to keep the same number

as in the original story.

When I first gave the above puzzle in a London newspaper, in

competition, no correct solution was received, but an ingenious and

neatly executed attempt by a man lying in a London infirmary was

accompanied by the following note: "Having no compasses here, I was

compelled to improvise a pair with the aid of a small penknife, a bit of

firewood from a bundle, a piece of tin from a toy engine, a tin tack,

and two portions of a hairpin, for points. They are a fairly serviceable

pair of compasses, and I shall keep them as a memento of your puzzle."

Amusements in Mathematics · 第 665 / 970 题