In 2010, as the Colombian government was preparing to rescue 16 soldiers held by armed FARC guerrillas, it looked in vain for a way to alert the soldiers without tipping off their captors. Finally Colonel Jose Espejo arranged to have local radio stations broadcast a pop song that contained a message in Morse code, which the soldiers had learned in basic training but that the guerrillas likely wouldn’t recognize.

The lyrics run, “In the middle of the night / Thinking about what I love the most / I feel the need to sing … About how much I miss them.” And hidden at three points in the song (1:30, 2:30, 3:30), in Morse code, is the message “19 people rescued. You are next. Don’t lose hope.”

“The hostages were listening to our own stations, so we made sure the song was played,” Espejo told The Verge. “The code message said, ‘you’re next’ because the hostages thought if they ran away, they would die in the jungle. We let them know that our troops were nearby.”

It worked. “We know of hostages who heard the message,” Espejo said, “and were able to escape and provide information that led to the release of more hostages.”

Introduced by Eberhard Faber in 1934, the Blackwing 602 premium writing pencil was stamped with the words “Half the Pressure, Twice the Speed”: Compared to an ordinary pencil, its core contained more graphite, less clay, and wax, so that it wrote like a pencil of 4B hardness but with a unique gliding feel.

It has attracted an impressive roster of creative admirers, including Walt Disney, Stephen Sondheim, Quincy Jones, Vladimir Nabokov, and John Steinbeck, who wrote, “I have found a new kind of pencil — the best I have ever had. Of course it costs three times as much too, but it is black and soft but doesn’t break off. I think I will always use these. They are called Blackwings and they really glide over the paper.”

Steinbeck would use a Blackwing pencil right down to the ferrule (pencil devotees now call this “Steinbeck stage”) and then pass them on to his son, another writer. “Writing with a Blackwing 602, more than any other pencil, feels like an event — something like a rite of passage for a pencil obsessive,” writes Caroline Weaver in The Pencil Perfect: The Untold Story of a Cultural Icon (2017). “When they are sold in my shop I always encourage the customer to sharpen it at least once and to use it for special occasions, because most of the pleasure of owning it comes from knowing what it feels like to write with it as much as it comes from the history.”

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.

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.)