Annie, Betty, Carrie, Darla, and Eve all have the same birthday, but all are different ages. On their shared birthday:

• Darla said to Betty: “I’m 9 years older than Eve.”
• Eve said to Betty: “I’m 7 years older than Annie.”
• Annie said to Betty: “Your age is exactly 70 percent greater than mine.”
• Betty said to Carrie: “Eve is younger than you.”
• Carrie said to Darla: “The difference between our ages is 6 years.”
• Carrie said to Annie: “I’m 10 years older than you.”
• Carrie said to Annie: “Betty is younger than Darla.”
• Betty said to Carrie: “The difference between your age and Darla’s is the same as the difference between Darla’s and Eve’s.”

Whenever one of them spoke to someone older than herself, everything she said was true, but when she spoke to someone younger, everything she said was false. How old is each person?

From 1906 to his death in 1922, Hungarian novelist Géza Gárdonyi kept a secret journal in a script so inscrutable that it wasn’t deciphered until 1965. He’d labeled the work a Tibetan grammar, but in fact it employed a calligraphic code founded in Hungarian using symbols that Gárdonyi had devised himself. In it he recorded his thoughts, observations, and literary plans. It was published in 1974 as Titkosnapló (“secret diary”).

“In science one tries to tell people, in such a way as to be understood by everyone, something that no one ever knew before. But in the case of poetry, it’s the exact opposite!” — Paul Dirac

For his 1959 work Zone de Sensibilité Picturale Immatérielle, Yves Klein sold the ownership of empty space.

In its 1967 Air-Conditioning Show, English conceptual collaborative Art & Language presented an empty room containing two air conditioning units; the artwork was “what is felt and said about it.”

James Lee Byars’ 1969 work The Ghost of James Lee Byars consisted of the emptiness and darkness of a pitch-black room.

Robert Barry communicated his 1969 Telepathic Piece mentally to visitors; the artwork was “a series of thoughts that are not applicable to language or image.”

Andy Warhol’s 1985 Invisible Sculpture was entirely intangible.

Tom Friedman’s 1992 work Untitled (A Curse)” consisted of a region of empty space that had been cursed by a witch.

Roman Ondak’s 2006 work More Silent Than Ever was an empty exhibition room in which a covert listening device had allegedly been hidden; visitors were told they were being monitored, but no evidence was ever given that the device really existed.

Salvatore Garau’s 2021 sculpture Io Sono occupied an area 5 feet square but was otherwise imperceptible.

Ruben Gutierrez’s 2022 work This Sculpture Makes Me Cry (A Spell) was said to represent what the artist could not see but which affected him emotionally.

Warhol and Gutierrez both presented their sculptures on white pedestals. Is there any way to prove they’re not the same piece?

In 1952, British computer scientist Christopher Strachey taught the Manchester Mark 1 computer to write love letters:

Darling Sweetheart,

You are my avid fellow feeling. My affection curiously clings to your passionate wish. My liking yearns for your heart. You are my wistful sympathy: my tender liking.

Yours beautifully

M. U. C.

Strachey’s original program has been lost, but it was reimplemented by MIT digital media professor Nick Montfort in 2014, and now you can watch it pour out its heart online. (Here’s a PHP implementation.)

A puzzle by N. Avilov, from the Russian science magazine Kvant. Prove that the shaded region of this pentagram takes up half its area.

Okay, that’s enough of that.

After 17 years, I think I’m going to take a bit of a break for a little while. I may post irregularly while I decide whether to continue.

In the meantime the blog archive and the podcast are still available. Thanks, as always, for reading!

Greg

P.S. Wow, thanks for all your kind messages! There are too many to respond to, but I’m reading every one. Thanks again!

A Slander traveling rapidly through the land upon his joyous mission was accosted by a Retraction and commanded to halt and be killed.

‘Your career of mischief is at an end,’ said the Retraction, drawing his club, rolling up his sleeves and spitting on his hands.

‘Why should you slay me?’ protested the Slander. ‘Whatever my intentions were, I have been innocuous, for you have dogged my strides and counteracted my influence.’

‘Dogged your grandmother!’ said the Retraction, with contemptuous vulgarity of speech. ‘In the order of nature it is appointed that we two shall never travel the same road.’

‘How then,’ the Slander asked, triumphantly, ‘have you overtaken me?’

‘I have not,’ replied the Retraction; ‘we have accidentally met. I came round the world the other way.’

But when he tried to execute his fell purpose he found that in the order of nature it was appointed that he himself perish miserably in the encounter.

— Ambrose Bierce, Fantastic Fables, 1899