The Falling Chain

Here are two identical rope ladders with slanting rungs. One falls to the floor, the other onto a table. The ladders are released at the same time and fall freely, but the one on the left falls faster, as if the table is “sucking” it downward. Why does this happen?

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Perspective

perspective puzzle

AB and CD are consecutive ties across a pair of railroad tracks that appear to meet at O on the horizon, H. If the ties are parallel to the horizon and are equally spaced along the tracks, how can we draw the next tie in this perspective figure?

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Black and White

spencer chess problem

G.B. Spencer devised this ingenious diagram in 1906: It contains 16 separate chess problems, one on each rank and file. In each case, ignore the pieces not on that rank or file and find a way for White to mate in two moves.

For example, the solution to the problem on the first rank is 1. Bd4 Ke2 2. Ng3#. What are the other 15 solutions?

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Reading a Pitch

In 1972, Addison-Wesley published an ad for three textbooks on the back of The American Statistician magazine. The ad began with this line:

Y LUAEB H O DTYO AOOSGL

In Word Ways, David Silverman wrote, “Care to try and figure out the hidden message? Although the slogan doesn’t have the pizzazz of (say) ‘Let Esso put a tiger in your tank’, it does have the advantage of universality; it can equally well be applied to the sale of shoes, ships or sealing wax (or, for that matter, floor wax).”

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Dinner Wit

It’s said that when Frederick the Great hosted Voltaire at Sanssouci Palace, he sent him this puzzling note:

https://commons.wikimedia.org/wiki/File:Frederick-rebus.png
Image: Wikimedia Commons

It’s a rebus in French: deux mains sous Pé à cent sous scie? (“two hands under ‘p’ at hundred under saw”) means demain souper à Sanssouci? (“supper tomorrow at Sanssouci?”).

Voltaire replied “Ga!”: Gé grand, A petit! (“big ‘G’, small ‘a’!”) means j’ai grand appétit!, or “I am very hungry!”

Town and Country

https://pixabay.com/en/chess-player-chess-game-play-chess-122966/

More chess masters reside in New York City than in the rest of the United States combined. We’re planning a chess tournament that all American masters are expected to attend, and we want to minimize the total intercity traveling done by the players. The New York players argue that, by this criterion, the tournament should be held in their city. The West Coast players argue that a city should be chosen near the center of the gravity of the players. Where should we hold the tournament?

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Mass Transit

https://pixabay.com/en/buses-traffic-stockholm-718876/

A city has 10 bus routes. Is it possible to arrange the routes and bus stops so that if one route is closed it’s still possible to get from any one stop to any other (possibly changing buses along the way), but if any two routes are closed, there will be at least two stops that become inaccessible to one another?

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