All’s Fair

https://books.google.com/books?id=ANI1AQAAMAAJ&pg=PA72

History’s ancient example of camouflage, the Trojan Horse, has a modern variation of peculiar interest. During the fighting near Craonne on the western front, some time ago, a horse broke his traces and dashed across ‘No Man’s Land’ toward the German defenses. When near the edge of a first-line trench he fell. The French immediately made the best of the opportunity and set camouflage artists at work fashioning a papier-mâché replica of the dead animal. Under cover of darkness the carcass was replaced with the dummy. For three days observers stationed in the latter were able to watch the enemy’s movements at close range and telephone their information to headquarters. Finally, when one observer was relieving another, the Germans discovered they had been tricked, and destroyed the post.

“Observer Hides in Dummy Horse Near Enemy Trench,” Popular Mechanics 29:1 (January 1918), 72.

On another occasion, a standing tree, whose branches had all been shot away, was carefully photographed and an exact copy of it made, but with a space inside in which an observer could be concealed. One night, while the noise of the workmen was drowned by heavy cannonading, this tree was replaced by its facsimile. And there it remained for many a day before the enemy discovered that it was a fake tree-trunk. It provided a tall observation-post from which an observer could direct the fire of his own artillery.

— A. Russell Bond, “Warriors of the Paint-Brush,” St. Nicholas 46:6 (April 1919), 499-505.

Twice True

SEVEN PLUS TWO = EIGHTEEN MINUS NINE = EIGHTEEN OVER TWO

That’s true enough on its face. But Susan Thorpe discovered that if each letter is replaced with the number of its position in the alphabet (A=1, B=2, etc.), then the equivalence persists — the values in each of the three phrases total 191.

(Susan Thorpe, “Number Name Equations,” Word Ways 30:1 [February 1997], 34-36.)

10/25/2020 UPDATE: Reader Jacob Bandes-Storch has found many more of these:

SIX OVER TWO PLUS TEN (277)
= FOUR MINUS ONE PLUS TEN (277)
= EIGHT OVER TWO PLUS NINE (277)
= ONE PLUS FIVE PLUS SEVEN (277)
= TWENTY SIX OVER TWO (277)

ONE PLUS ONE PLUS TWELVE (291)
= ONE PLUS TWO PLUS ELEVEN (291)
= TWO PLUS TWO PLUS TEN (291)
= FIFTEEN OVER THREE PLUS NINE (291)
= EIGHT MINUS THREE PLUS NINE (291)

FIFTEEN OVER THREE PLUS ELEVEN (312)
= EIGHT MINUS THREE PLUS ELEVEN (312)
= TWELVE OVER TWO PLUS TEN (312)
= ELEVEN MINUS THREE PLUS EIGHT (312)

FIFTEEN PLUS FORTY THREE = TWENTY NINE TIMES TWO = SEVENTY MINUS TWELVE (273)

THIRTEEN PLUS FIFTY SIX = TWENTY THREE TIMES THREE = EIGHTY EIGHT MINUS NINETEEN (285)

NINETEEN PLUS FIFTY THREE = THIRTY SIX TIMES TWO = SEVENTY THREE MINUS ONE (276)

TWO PLUS SEVENTY THREE = ONE HUNDRED FIFTY OVER TWO = NINETY THREE MINUS EIGHTEEN (292)
SEVENTEEN PLUS FIFTY EIGHT = ONE HUNDRED FIFTY OVER TWO = NINETY THREE MINUS EIGHTEEN (292)

FORTY PLUS FORTY FIVE = TWENTY EIGHT TIMES THREE = NINETY SIX MINUS ELEVEN (278)

TWO PLUS NINETY SEVEN = THIRTY THREE TIMES THREE = ONE HUNDRED FIVE MINUS SIX (also 278)

He says he hasn’t found any quadruplets where each phrase uses a single function and all are different, but this may yet be possible. (Thanks, Jacob.)

Podcast Episode 307: The Cyprus Mutiny

https://commons.wikimedia.org/wiki/File:Watercolour_of_the_brig_Cyprus_(1830).jpg
Image: Wikimedia Commons

In 1829 a group of convicts commandeered a brig in Tasmania and set off across the Pacific, hoping to elude their pursuers and win their freedom. In this week’s episode of the Futility Closet podcast we’ll describe the mutineers of the Cyprus and a striking new perspective on their adventure.

We’ll also consider a Flemish dog and puzzle over a multiplied Oscar.

See full show notes …

Voting With One’s Feet

https://www.flickr.com/photos/ubidesperarenescio/8359328152
Image: Flickr

The paved walkways in Ohio State University’s central Oval were not laid at the university’s founding — rather, as the campus buildings were erected in the early 20th century, students began to wear natural paths in the grass as they made their way to the most popular destinations, and these paths informed the modern pattern of paved walks.

Such routes are known as “desire paths” — urban planners will sometimes study the tracks in new-fallen snow to understand where foot traffic naturally “wants” to go.

A Bimagic Queen’s Tour

walkington semi-bimagic queen's tour
Image: William Walkington (CC BY-NC-SA 4.0)

A queen’s tour is the record of a chess queen’s journey around an empty board in which she visits each of the squares once. If the squares are numbered by the order in which she visits them, then the resulting square is magic if the numbers in each rank and file sum to the same total. It’s bimagic if the squares of these numbers also produce a consistent total.

William Walkington has just found the first bimagic queen’s tour, which also appears to be the first bimagic tour of any chess piece. (William Roxby Beverley published the first magic knight’s tour in The London, Edinburgh, and Dublin Philosophical Magazine and Journal of Science in 1848.)

Note that here the long diagonals don’t produce the magic sum, as they would in a magic square. This constraint is normally dropped in a magic tour — in fact, of the 140 magic knight tours possible on an 8×8 board, none have two long magic diagonals, and no bimagic queen’s tour with qualifying diagonals is possible on such a board either.

More details, and an interesting description of the search, are on William’s blog. He has been told that a complete list of such bimagic queen’s tours is within reach of a computer search, though the field is daunting — there are more than 1.7 billion essentially different semi-bimagic squares possible on an 8×8 board, and each allows more than 400 million permutations.

The Isolator

https://manifold.umn.edu/read/the-perversity-of-things-hugo-gernsback-on-media-tinkering-and-scientifiction/section/69697807-3c5f-4de5-aa3b-d070728205f9

Irritated with distractions in his editorial work, Hugo Gernsback designed a helmet “to do away with all possible interferences that prey on the mind”:

The first helmet constructed as per illustration was made of wood, lined with cork inside and out, and finally covered with felt. There were three pieces of glass inserted for the eyes. In front of the mouth there is a baffle, which allows breathing but keeps out the sound. The first construction was fairly successful, and while it did not shut out all the noises, it reached an efficiency of about 75 per cent. The reason was that solid wood was used.

In a later version he omitted the wood and added an air space between layers of cotton and felt, achieving an efficiency of 90 to 95 percent. Even the eyepieces are black except for a single slit, to prevent the eyes from wandering. “With this arrangement it is found that an important task can be completed in short order and the construction of the Isolator will be found to be a great investment.”

(He even designed an ideal office, with a soundproof door, triple-paned windows, and felt-filled walls, in which to wear this — see the illustration at the link below.)

(Hugo Gernsback, “The Isolator,” Science and Invention 13:3 [July 1925], 214ff.)

Memorial

https://commons.wikimedia.org/wiki/File:Anthem_Veterans_Memorial_(15585427880)_crop.jpg
Image: Wikimedia Commons

The Anthem Veterans Memorial, in Anthem, Arizona, consists of five white pillars representing the Army, Marine Corps, Navy, Air Force, and Coast Guard. Each pillar contains a slanted elliptical opening, and the five are arranged so that at 11:11 a.m. on Veterans Day, November 11, the sun’s light passes through all five and illuminates the Great Seal of the United States, which is inlaid among 750 red paving stones engraved with the names of veterans.

An Odd Word

https://commons.wikimedia.org/wiki/File:Ha_ha_wall_diagram.jpg
Image: Wikimedia Commons

In E.M. Forster’s 1907 novel The Longest Journey, the description of the country estate Cadover contains a surprising term:

The lawn ended in a Ha-ha (‘Ha! ha! who shall regard it?’), and thence the bare land sloped down into the village.

A ha-ha is indeed the term for a sort of buried wall adjoined by a sloping ditch — it will keep deer out of your garden without blocking the view. But how it came by that name seems uncertain. Possibly it’s a shortened form of “half and half” (half wall, half ditch), and possibly it’s named for the cries of its observers — the earliest usage in the Oxford English Dictionary is John James’ 1712 translation of Antoine-Joseph Dézallier d’Argenville’s Theory and Practice of Gardening — he refers to “a large and deep Ditch at the Foot.., which surprizes..and makes one cry, Ah! Ah! from whence it takes its Name.”

In Terry Pratchett’s novel Men at Arms, a ha-ha is accidentally specified to be 50 feet deep. The result is called a hoho, and it claims the lives of three gardeners. In Snuff, two characters go for a walk in the countryside and “navigate their way around the ha-ha, keep their distance from the ho-ho and completely ignore the he-he.”

Moving Words

In October 1996, Parade magazine published the results of a vanity license plate contest that received more than 7,000 entries. Here are the 10 winning plates:

  1. IRIGHTI
  2. RUD14ME?
  3. HAHAHAHA
  4. XQQSME
  5. IM12XL
  6. ULIV1S
  7. AXN28D+
  8. VAN GO
  9. H2OUUP-2
  10. TI-3VOM

What are their meanings?

Click for Answer