In 1822, when Europeans were still searching for an explanation for the annual disappearance of some bird species, a white stork appeared bearing a central African arrow in its neck. This helped to show that some birds migrate long distances for the winter.
The stuffed stork can be seen today at the University of Rostock, where it bears the magnificent name Rostocker Pfeilstorch (“arrow stork from Rostock”).
Stack two of the bricks and place the third alongside. Now you’ve identified the corners of an invisible fourth brick, whose diagonal you can measure directly with the ruler.
(Bonus: If the bricks’ edges and face diagonals all have integer lengths, and you find that the interior diagonal is an integer as well, you’ll have solved an open problem in mathematics.)
01/03/2021 UPDATE: Reader Paul-Georg Becker points out that the task can be accomplished with two bricks and a ruler:
A hyperbola is the locus of points the difference of whose distances from two fixed points is a constant. In this case that constant is the distance that sound travels in the length of time it takes the bullet to reach the target. The man can stand anywhere on the branch of the hyperbola nearer to the target — “but hopefully not at the vertex.”
(Proposed by Thomas Dobson of Hexham, England; solved by C.W. Dodge of the University of Maine, Orono, in Fall 1969 [Volume 5, Issue 1].)
On the second day of Apollo 16’s trip to the moon in 1972, command module pilot Ken Mattingly lost his wedding ring. “It just floated off somewhere, and none of us could find it,” lunar module pilot Charlie Duke told Wired in 2016.
Mattingly looked for it intermittently over the ensuing week, with no luck. By the eighth day, Duke and Commander John Young had visited the moon and rejoined him, but there was still no sign of the ring.
But during a spacewalk the following day, Mattingly was just heading back toward the open hatch when Duke said, “Look at that!” The ring was floating just outside the hatch. “I grabbed it,” he said, “and we put it in the pocket. We had the chances of a gazillion to one.”
Duke said later, “You plan and plan and plan but the unexpected always jumps up and bites you.”
(From Ben Evans, Foothold in the Heavens: The Seventies, 2010.)
A stunning geometric alphamagic square by Lee Sallows. The 3 × 3 grid is a familiar magic square in which each number is spelled out: The first cell contains the number 25, the second 2, and so on. Interpreted in this way, each row, column, and long diagonal sums to 45.
But there’s more: The English name of the number in each cell has been arranged onto a distinctive tile, such that the three tiles in any row, column, or long diagonal can be combined to form the same 21-cell figure, as shown. (Shapes with dotted outlines have been turned over.)
And yet more: Count the number of letters in each of the number names (or, equivalently, count the number of cells that make up each tile). So, for example, TWENTY-FIVE has 10 letters, so replace the TWENTYFIVE tile with the number 10. Similarly, replace TWO with 3, EIGHTEEN with 8, and so on. This produces another magic square:
I’m just sharing this because I think it’s pretty — it’s the smallest arrangement of identical non-crossing matchsticks that one can make on a tabletop in which each match-end touches three others.
Presented by German mathematician Heiko Harborth in 1986, it’s known as the Harborth graph.
A perplexing story from logician Raymond Smullyan:
Oh, one other thing. I must tell you of a certain great Sage in the East who was reputed to be the wisest man in the world. A philosopher heard about him and was anxious to meet him. It took him fifteen years to find him, but when he finally did, he asked him: ‘What is the best question that can be asked, and what is the best answer that can be given?’ The great Sage replied: ‘The best question that can be asked is the question you have asked, and the best answer that can be given is the answer I am now giving.’
It’s at the very end of his last book, A Mixed Bag, from 2016.
A normal die is painted so that it has four green faces and two red. Then it’s shaken in a cup and thrown repeatedly onto a table. You’re invited to guess which of these three sequences results. If you guess wrong you lose $10; and if you guess right you win $30.
RGRRR
GRGRRR
GRRRRR
Most people express the preferences 2, 1, 3, in that order. Red is less likely than green, but it predominates in all three sequences, so many subjects explain that sequence 2 is more “balanced,” and therefore more probable. In fact 65 percent of all subjects (excluding expert statisticians and people whose business is probability) show a strong propensity to vote for sequence 2, even when it’s pointed out explicitly that sequence 1 is just sequence 2 minus the first throw — so sequence 2 cannot be more likely!
“The longer the sequence, the less probable it is, independently of its being ‘balanced’ or ‘unbalanced,'” writes Massimo Piattelli-Palmarini in Inevitable Illusions. “This shows how resistant certain cognitive illusions are. Many other more complex examples have been advanced, and these show that even professional statisticians are sometimes subject to the same illusion.”
In Season 8, Episode 7 of Penn & Teller’s magic competition show Fool Us, magician Hans Petter Secker appears to predict the outcome of three successive rounds of rock-paper-scissors, though Secker oversees the game remotely from Norway and the players are invited to exchange items before each round. How is this accomplished?
No matter which object you hold (rock, paper, or scissors), your object beats one of the other two and loses to one of the other two.
The performer’s first prediction names one result (Teller beats Penn), but the other two results follow from that prediction: Teller’s object loses to Alyson’s, and Penn’s object beats Alyson’s.
In the second round, the performer names two results (Alyson beats Teller and Penn beats Alyson), but this is no more of a feat than naming one result. It’s a cute bit of showmanship that it seems like he’s predicting more with each round.
There are six ways to permute three objects. But in terms of who beats who, there are only two possible states:
Penn beats Teller; Teller beats Alyson; Alyson beats Penn
Teller beats Penn; Alyson beats Teller; Penn beats Alyson
A swap — any swap — inverts the state. An even number of swaps preserves the state.
The performer controlled the initial state by the order the objects were placed in the box. He asked Penn to grab the object on top (rock), Teller to grab the next one (scissors), Alyson to grab the remaining object (paper). That’s an instance of state 1 as described above.
After one swap, we have state 2. It doesn’t matter which pair of people swapped. For the next round, two more swaps maintains state 2. For the final round, three more swaps returns to state 1.
Tom writes, “To most observers, the later rounds seem like harder feats of prediction because the number of swaps increases with each round — but it’s all simple.”
Just a charming little anecdote: When German chemist Adolf von Baeyer achieved a long-sought result, he tipped his hat to it:
Eventually, however, even Baeyer was supersaturated with these hydrogenations, and the sorely tried assistants hailed with deep relief the transference of his interest to succinylsuccinic ester and diketocyclohexane. By means of a dodge (‘Kunstgriff’) of which Baeyer was very proud (treatment with sodium amalgam in presence of sodium bicarbonate), the diketone was reduced to quinitol. At the first glimpse of the crystals of the new substance Baeyer ceremoniously raised his hat!
It must be explained here that the Master’s famous greenish-black hat plays the part of a perpetual epithet in Prof. Rupe’s narrative. As the celebrated sword-pommel to Paracelsus, so this romantic hard-hitter or ‘alte Melone’ to Baeyer: the former was said to contain the vital mercury of the mediaeval philosophers; the latter certainly enshrined one of the keenest chemical intellects of the modern world. … Baeyer’s head was normally covered. Only in moments of unusual excitement or elation did the Chef remove his hat: apart from such occasions his shiny pate remained in permanent eclipse.
(From his colleague John Read’s 1947 book Humour and Humanism in Chemistry.)