The UTA Flight 772 Memorial

In 1989 a DC-10 en route from Brazzaville to Paris exploded and crashed in the Sahara Desert, hundreds of miles from the nearest town. Six Libyans were convicted in absentia for planting a suitcase bomb on the flight.

In 2007, the families of the victims used compensation funds paid by Libya to build a memorial at the crash site in the Niger desert. With the help of 140 locals from Agadez, the nearest city, they trucked in dark stones to create a 200-foot circle surrounding a silhouette of the plane and arranged 170 broken mirrors around the perimeter, one for each victim. At the site’s northern compass point stands the crashed plane’s starboard wing, bearing the names of the passengers.

The site can still be seen on Google Earth as it’s slowly reclaimed by the desert.

https://commons.wikimedia.org/wiki/File:M%C3%A9morial_du_Vol_772_de_l_UTA.jpg
Image: Wikimedia Commons
| History

Dear Sirs

Here’s a letter that might have been received by the Restormel County Council. What’s unusual about it?

Dear Sirs:

I shed no tears to learn that the hill in Mansion Road, close to most locals’ homesteads, is at last considered at least a minor threat to residents in the area. At times in the cold season the ice created on this road is a colossal attraction to the local children. Some slither and slide on the ice on sleds, tin sheets, etc, to their hearts’ content, and create concerns to motorists, and others in the area, in the colder months. It is nice to see that this matter is at last in hand, to note its consideration as an essential element in Restormel’s schemes to decrease the district’s road accidents.

A Contented Resident.

Click for Answer
| Language

Knights and Knaves

A logic puzzle by MIT mathematician Tanya Khovanova: You’re visiting an island on which every resident is either a knight or a knave. Knights always tell the truth, and knaves always lie. All the islanders know one another. You meet three islanders, Alice, Bob, and Charlie, and ask each one, “Of the two other islanders here, how many are knights?” Alice says, “Zero.” Bob says, “One.” What will Charlie say?

Click for Answer
| Puzzles

The Silurian Hypothesis

https://commons.wikimedia.org/wiki/File:Iss007e10807.jpg

Complex life has existed on Earth’s land surface for about 400 million years, and our civilization has been here for only a tiny fraction of that. If another industrial society had arisen millions of years ago, what traces could we still hope to find?

Astrobiologists Gavin Schmidt and Adam Frank point out that, while we might search the geologic record for evidence of plastics, synthetic pollutants, and increased metal concentrations, that expectation is based only on our own history, and a more enlightened civilization might leave a smaller footprint by using more sustainable practices (indeed, such a society is likely to survive longer).

Ironically, a poorly managed industrial civilization may deplete dissolved oxygen in the oceans, leading to an increase in organic material in the sediment, which can serve as a source of future fossil fuels. “Thus, the prior industrial activity would have actually given rise to the potential for future industry via their own demise.”

See the link below for the full paper.

(Gavin A. Schmidt and Adam Frank, “The Silurian Hypothesis: Would It Be Possible to Detect an Industrial Civilization in the Geological Record?”, International Journal of Astrobiology 18:2 [2019], 142-150.)

| Science & Math

To Your Door

Architect Leroy L. Warner introduced a new concept in 1950: “Park at Your Desk.” The center of the Cafritz office building in Washington, D.C., was a multi-story parking garage with a helical ramp, and set around this core was a ring of shallow day-lit offices. So each worker could drive into the building, drive up to their floor, park their car, and then walk just a few meters to the office.

Why didn’t this catch on? Architect Philip Steadman points out that the design constraints allowed for 150 people per floor but only 29 parking spaces, a bad mismatch. (Also, “One wonders about air quality in the offices.”)

(From Philip Steadman, Why Are Most Buildings Rectangular?, 2017.)

| Society · Technology

A Planned And

Martin Gardner offered this curiosity in the August 1998 issue of Word Ways: Roll two six-sided dice. If they show a total of 6 or 8, roll them again. Otherwise, go to the chapter of Genesis (the King James version) that corresponds to the total on the dice. Now turn both dice upside down and go to the verse whose number is now displayed. The first word of that verse will always be And.

(Martin Gardner, “Mysterious Precognitions,” Word Ways 31:3 [August 1998], 175-177.)

| Literature · Oddities

Pangrammatic Loops

A marvelous variation on self-inventorying lists, from the inimitable Lee Sallows:

Recalling that a self-enumerating pangram corresponds to a closed loop of length 1, here follows a loop of length 2, which is to say, a pair of pangrams that enumerate each other. The pangrams are both minimal in the sense of containing none but essential letters with no “and”s or other devices openly or surreptitously added.

ONE A, ONE B, ONE C, ONE D, THIRTYONE E, FOUR F, ONE G, FIVE H, FIVE I, ONE J, ONE K, ONE L, ONE M, TWENTYTWO N, SEVENTEEN O, ONE P, ONE Q, SEVEN R, FOUR S, ELEVEN T, THREE U, FIVE V, FOUR W, ONE X, THREE Y, ONE Z.

ONE A, ONE B, ONE C, ONE D, THIRTYTWO E, SEVEN F, ONE G, FOUR H, FIVE I, ONE J, ONE K, TWO L, ONE M, TWENTY N, NINETEEN O, ONE P, ONE Q, SEVEN R, THREE S, NINE T, FOUR U, SEVEN V, THREE W, ONE X, THREE Y, ONE Z.

An alternative (non-minimal) pair includes plural s’s:

ONE A, ONE B, ONE C, ONE D, TWENTYSEVEN E’S, SIX F’S, ONE G, THREE H’S, SIX I’S, ONE L, TWENTY N’S, SIXTEEN O’S, ONE P, ONE Q, SIX R’S, NINETEEN S’S, TWELVE T’S, FOUR U’S, FOUR V’S, FIVE W’S, THREE X’S, FOUR Y’S, ONE Z.

ONE A, ONE B, ONE C, ONE D, TWENTYNINE E’S, FIVE F’S, ONE G, THREE H’S, SEVEN I’S, ONE J, ONE K, TWO L’S, ONE M, TWENTY N’S, SIXTEEN O’S, ONE P, ONE Q, SIX R’S, TWENTY S’S, TEN T’S, FOUR U’S, THREE V’S, FOUR W’S, FIVE X’S, THREE Y’S, ONE Z.

In similar vein, pangrammatic loops of length 3 follow, but now in shorthand, using arabic numerals to stand for number words, i.e. 1 = one, 2 = two, etc. The first list is enumerated by the second, the second by the third and the third by the first. The 1st loop contains minimal pangrams, the 2nd, pangrams with plural s’s:

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z
1  1  1  1 31  5  1  5  9  1  1  1  1 20 16  1  1  5  5 11  1  4  3  4  2  1
1  1  1  1 28  7  1  3  8  1  1  2  1 20 18  1  1  5  2  8  3  6  3  2  3  1
1  1  1  1 31  2  5  9  7  1  1  1  1 16 15  1  1  5  3 16  1  3  6  2  3  1

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z
1  1  1  1 32  5  2  3  7  1  1  1  1 22 18  1  1  3 19 14  2  6  7  2  3  1
1  1  1  1 32  3  2  6  6  1  1  1  1 20 18  1  1  6 19 16  2  4  7  2  3  1
1  1  1  1 27  2  2  5  8  1  1  1  1 19 17  1  1  5 21 14  2  2  6  5  3  1

Here also a minimal pangrammatic loop of length 4 (no equivalent using plural s’s exists):

A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z
1  1  1  1 25  4  2  4  7  1  1  2  1 16 18  1  1  5  5 11  3  4  5  4  2  1
1  1  1  1 28  9  2  3  7  1  1  2  1 16 18  1  1  6  3  9  5  7  5  2  2  1
1  1  1  1 30  3  3  5  9  1  1  1  1 20 15  1  1  3  5 12  1  5  6  3  2  1
1  1  1  1 30  6  1  6  8  1  1  2  1 17 14  1  1  6  2 12  1  5  4  2  3  1

“There exist no minimal pangrammatic loops of length 5 or longer until we reach lengths 10, 33, and 55 (no plural s’s) and lengths 15, 22, 23, 207 and 312 (with plural s’s),” he adds. “This completes what I believe to be an exhaustive survey of all self-enumerating minimal pangrammatic loops.”

(Thanks, Lee.)

| Language · Science & Math