The Puzzle That Will Outlast the World

The package I’ve been impatiently waiting for finally arrives: A cardboard box about as tall as your average Olympic gymnast. It’s covered in yellow packing tape, stamped fragile, and has a return address in a town in the Netherlands.

Inside this box is a thing of beauty—and absurdity. It’s a one-of-a-kind puzzle created just for me by one of the greatest puzzle makers in the world. It is, almost surely, the hardest puzzle ever to exist. But before I open the box, let me tell you how the puzzle came to be, and why I think it’s not a trivial pursuit.

To do that, I’ll need to start with the Chinese ring puzzle. I was introduced to it by a puzzle collector named Wei Zhang, who, along with her husband, Peter Rasmussen, is famous in the puzzle community for having one of the world’s best collections of Chinese puzzles. Also called a “patience puzzle,” the ring puzzle dates back about 2,000 years, at least in its simplest form. What particularly fascinates me about this kind of puzzle is that it’s recursive: It gets much, much harder the more rings it has.

The goal is simple: remove a set of rings from a bar to which they’re attached. But the catch is that, for each additional ring, you have to make an exponentially greater number of moves. Solving a three-ring puzzle takes only five moves. But a six-ring puzzle takes 42 moves. A nine-ring puzzle takes 341 moves. This is because, to remove the ninth ring, you first have to repeat the entire process of removing the first ring, the second ring, the third ring, and so on. Imagine if you had to run a marathon, but at every additional mile, you had to return to the starting line and repeat the entire sequence that got you there.

A diagram of a recursive marathon

You see how many miles you have to run to get to even the third-mile marker? If I actually did the diagram for 26 miles, the book this article is excerpted from would be taller than the Eiffel Tower. That’s a recursive pattern.

Turns out, the ring puzzle has several cousins in the puzzle family tree. They are called “generation puzzles,” because they take generations to solve. You’re supposed to pass them on to your kids, who pass them on to their kids, who pass them on to their kids, and on and on.

I love this idea—the ambitious scope, the connection to my descendants. I’ve always wanted an heirloom that I can hand to my sons on my deathbed. The closest I have is a blazer my grandfather gave me—it’s red-and-white checkered and could double as a tablecloth at an Italian bistro. It’s fraying and won’t last. But a generation puzzle? That would be perfect. It’d be an amazing reminder of the vastness of time. I recently interviewed a mathematician who told me that gazing at space made her feel like she was touching infinity. This would be my version of that.

But first, I needed a collaborator. A friend suggested that I contact a man named Oskar van Deventer, a Dutch puzzle creator. I’d often heard Oskar’s name dropped in puzzle circles. He’s considered one of the greats. He has made many famous puzzles, including a fractal jigsaw and a Rubik’s-type cube with gears and cogs on the outside. (He also caused a minor kerfuffle when he posted a video of a penis-shaped puzzle, a copy of which is now housed at the Kinsey Institute, a sex-research center.)

I called Oskar in the Netherlands and asked him if he could create a generation puzzle for me. “Let me think about it,” he said, with a hint of a Dutch accent. “I don’t want to just create a big Chinese ring puzzle. That would be boring.”

A few days later, Oskar emailed me a sketch. It looked like a cross between a Jenga tower, a giant corkscrew, and a girder from a skyscraper. The puzzle’s main wooden column was covered top to bottom with 55 interlocking wooden pegs, which together trapped a black corkscrew rod inside. The goal was to turn the pegs in the proper order to remove the rod. But the catch was that you have to turn the pegs many, many, many, many times.

The solver would start by twisting the bottommost couple of pegs in the proper sequence, allowing the corkscrew to move an inch or so upward before it got stuck again. To pull the corkscrew out farther, you would have to start over and repeat the sequence, and then also add an additional sequence for the third peg. And so on, until the 55th. It would be even more recursive than the Chinese ring puzzle: With every new level, instead of doubling, the number of moves required would go up by a factor of four. “We could call it ‘Jacobs’ Ladder,’” Oskar said.

I was sold. “Would it break the record?” I asked.

“I don’t know if I can do that,” he said. “But I can try.”

The current record for hardest-to-solve generation puzzle was a 65-ring Chinese puzzle owned by the collector Jerry Slocum. Solving it would take 18 quintillion moves. That’s a 1 followed by 19 zeros.

In the following weeks, Oskar sent me updates. Things were not going well. He’d tried to 3-D-print the puzzle out of gold-colored plastic, but it had melted and warped. He was worried it would be too big to ship to the United States. He had to take a week off to paint his house.

And then, on a Friday morning, I woke up to an email from Oskar. He had finished making the puzzle—and it worked. He had made a 55-pin Jacobs’ Ladder. Solving it would take 1.2 decillion moves (the number 1 followed by 33 digits). Written out, that’s: 1,298,074,214,633,706,907,132,624,082,305,023 moves.

We’d crushed the old record by 13 orders of magnitude. Oskar did some delightfully nerdy calculations on just how long it would take to solve this puzzle. If you were to twist one peg per second, he explained, the puzzle would take about 40 septillion years. By the time you solved it, the sun would have long ago destroyed the Earth and burned out. In fact, all light in the universe would have been extinguished. Only black holes would remain. Moreover, Oskar said, if only one atom were to rub off due to friction for each move, it would erode before you could solve it.

On a summer day, in our living room, with my wife and three sons assembled, I slice open the cardboard box. I pull out the Jacobs’ Ladder and put it on the floor. It’s about four feet tall. “One decillion moves to solve it,” I say. “It’s impossible for our brains to conceive of how many that is.”

The Jacobs's Ladder
The Jacobs’ Ladder

Jacobs’ Ladder is a physical manifestation of so much of what I love about puzzles. Doing them can make us better thinkers—more creative and more incisive. Jacobs’ Ladder may not offer the same logical and creative challenges that cryptics or chess problems do, but like all great puzzles, it contains lessons about ingenuity, fresh perspectives, and optimism. And for me, it has one more thing I value in puzzles: a meditative angle.

I’m terrible at just-sitting-and-breathing meditation, but Jacobs’ Ladder will be my version of meditation. I’ll let my thoughts flow in and out of my brain as I calmly twist the pegs. And it will teach me to be okay with lack of closure. As the late Maki Kaji—widely known as the godfather of Sudoku—told me in 2020, puzzles are a journey. He rendered the experience in three symbols:

? → !

Kaji said that the key is to embrace the middle part, the arrow, the journey. Don’t be obsessed with endings and perfection.

“It’s about the journey, not the destination!” my youngest son says, rolling his eyes.

“Exactly!” I say. “Except without the eye-roll part.” I twist one of the plastic pegs. It doesn’t turn easily. It gives resistance, like a cap on a soda bottle, makes a soft clunking sound, and then locks into place. I turn to my wife. “Okay, it’s your turn.”

One by one, each member of the family dutifully twists a peg. At least to me, it feels like a sacred ritual, like we are lighting the candles on a menorah, or ringing bells in a temple. I pledge to turn a peg every day. Or at least every week. Maybe every month. But we will do it.

“We’re on our way,” says my middle son.

It’s true. Only 1,298,074,214,633,706,907,132,624,082,305,018 moves to go.

This article was adapted from A. J. Jacobs’s forthcoming book, The Puzzler: One Man’s Quest to Solve the Most Baffling Puzzles Ever, from Crosswords to Jigsaws to the Meaning of Life.