Just found this on Wikimedia Commons — “Where Is the Fifth Pig?”, an anonymous puzzle created in occupied Holland in 1940:
Author: Greg Ross
A Little Clue
A circle is inscribed in a square, with a rectangle drawn from a corner of the square to a point on the circle, as shown. If this rectangle measures 6 inches by 12 inches, what’s the radius of the circle?
Also-Rans
“The dogs are, by placing two lines upon them, to be suddenly aroused to life and made to run. Query, How and where should these lines be placed, and what should be the forms of them?”
Backward and Forward
John Grant McLoughlin offered this problem in Crux Mathematicorum in April 2008:
Every four-digit numerical palindrome (e.g., 2772) is a multiple of 11. Why is this?
A Beautiful Relic
The River Welland used to split into two channels in the heart of Crowland, Lincolnshire, and in 1360 the townspeople arranged to bridge it with this unique triple arch, which elegantly spanned the streams at the point of their divergence, allowing pedestrians to reach any of the three shores by a single structure. The alternative would have been to build three separate bridges.
The rivers were re-routed in the 1600s, so now the bridge stands in the center of town as a monument to the ingenuity of its inhabitants. It’s known as Trinity Bridge.
From the ArtefactPorn subreddit.
Things to Come
An intriguing photo caption from A Mind at Play, Jimmy Soni and Rob Goodman’s 2017 biography of AI pioneer Claude Shannon:
Shannon set four goals for artificial intelligence to achieve by 2001: a chess-playing program that was crowned world champion, a poetry program that had a piece accepted by the New Yorker, a mathematical program that proved the elusive Riemann hypothesis, and, ‘most important,’ a stock-picking program that outperformed the prime rate by 50 percent. ‘These goals,’ he said only half-jokingly, ‘could mark the beginning of a phase-out of the stupid, entropy-increasing, and militant human race in favor of a more logical, energy conserving, and friendly species — the computer.’
Shannon wrote that in 1984. He died in 2001.
Our Best Friend
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Decisions
‘Suppose that a foolish man has seized hold of a plank from a sinking ship, shall a wise man wrest it away from him if he can?’
‘No,’ says Hecaton; ‘for that would be unjust.’
‘But how about the owner of the ship? Shall he take the plank away because it belongs to him?’
‘Not at all; no more than he would be willing when far out at sea to throw a passenger overboard on the ground that the ship was his. For until they reach the place for which the ship is chartered, she belongs to the passengers, not to the owner.’
‘Again; suppose there were two to be saved from the sinking ship — both of them wise men — and only one small plank, should both seize it to save themselves? Or should one give place to the other?’
‘Why of course, one should give place to the other, but that other must be the one whose life is more valuable either for his own sake or for that of his country.’
‘But what if these considerations are of equal weight in both?’
‘Then there will be no contest, but one will give place to the other, as if the point were decided by lot or at a game of odd and even.’
— Cicero, De Officiis, 44 BC
Fore!
Golfers at the Aroostook Valley Country Club have to play carefully — a stray shot might leave the country. The club straddles the border between the United States and Canada — the course and clubhouse are in New Brunswick, and the parking lot and pro shop are in Maine.
The club was launched in 1929, when enterprising founders built the clubhouse just feet inside the Canadian border, so that visiting American golfers could evade Prohibition without having to pass through customs.
Both nations still play the course today, but border restrictions imposed during the pandemic mean that Americans now have to enter at an official border crossing.
Point to Point
Nearly every station in the London Underground contains an enamel plaque depicting a labyrinth. The collection were installed in 2013 by artist Mark Wallinger to mark the system’s 150th anniversary. Each of the 270 black and white designs is unique to its location, and all of them are posted in publicly accessible locations, so visitors can examine them directly, tracing the path with a finger. They’re numbered according to the route taken by the contestants in a 2009 Guinness World Records challenge to visit all stations in the system in the fastest time.
A list of all 270 labyrinths is here.