Over time, Mr. Sanborn has tried to provide clues that could move people along, since he has been hounded by people who believe, mistakenly, that they have cracked the last passage, known as K4. He was getting 200 inquiries a week, he told me, which “became overwhelming and some became threatening and even, believe it or not, racist.” For $50, people could submit a proposed solution and get an answer, which “made things much more manageable,” he said.

He provided a clue to me in 2010 that we published in The New York Times. And again in 2014. And now.

He called me in late 2019 to suggest he might be about to release another clue, to move things along. At a recent gathering of Kryptos fans, he had said he wanted me to take it on. I said yes, of course.

I love Mr. Sanborn’s work. When I stumbled upon one of his unmistakable pieces on the campus of the University of Iowa, a metal cylinder with punched-through letters in many languages that is lit from within at night, casting text on the courtyard and walls around it, it seemed so instantly familiar that I felt as if I were encountering an old friend in a strange town.

But Kryptos, his decades-old piece, has become something of a millstone for him, he said. “My cryptography interest left me 25 years ago,” he told me as I was finishing the latest article. “My art went in different directions.” That’s an understatement. While he has produced other cryptographic pieces, he has also produced astonishing installations that straddle art and science, and, most recently, “Without Provenance: The Making of Contemporary Antiquity,” a collection of objects that explores the nature of looted antiquities and forgery in unsettling ways.

Perhaps the most interesting part of my call from Mr. Sanborn is his decision to arrange an auction to sell the solution to the mystery, whether after his death or before. If the amount of money raised is substantial — and this, he admits, is unknown — it will go to support climate science. He lives on an island in the Chesapeake Bay, so as he told me, it was a “no-brainer.” Coincidentally, this put the Kryptos news within my current beat.

As I worked on the story about the final clue, my editor, Hannah Fairfield, liked the graphics possibilities of portraying the coded and decoded passages; Jonathan Corum, the amazing science graphics editor, agreed to do his magic. And you can see the result.

Much of the time, journalism is jack rabbit quick, with the need to leap when news breaks.

Sometimes it’s slow, and things can percolate. And sometimes it even helps us solve a puzzle.

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