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See If You Can Solve This Tricky Coin-Flipping Riddle

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Make sure your head is in working order before trying to solve this riddle from TED-Ed, because it's a stumper.

Here's the scenario: You're an explorer who's just stumbled upon a trove of valuable coins in a remote dungeon. Each coin has a gold side and a silver side, each with an identical scorpion seal. The wizard who guards the coins agrees to let you have them, but he won't let you leave the room unless you separate the hoard into two piles with an equal number of coins with the silver side facing up in each. You've just counted the total number of silver-side-up coins—20—when the lights go out. In the dark, you have no way of knowing which half of a coin is silver and which half is gold. How do you divide the pile without looking at it?

As TED-Ed explains, the task is fairly easy to complete, no psychic powers required. All you need to do is remove any 20 coins from the pile at random and flip them over. No matter what combination of coins you choose, you will suddenly have a number of silver-side-up coins that's equal to whatever is left in the pile. If every coin you pulled was originally gold-side-up, flipping them would give you 20 more silver-side-up coins. If you chose 13 gold-side-up coins and seven of the silver-side coins, you'd be left with 13 silver coins in the first pile and 13 silver ones in your new stack after flipping it over.

The solution is simple, but the algebra behind it may take a little more effort to comprehend. For the full explanation and a bonus riddle, check out the video from TED-Ed below.

[h/t TED-Ed]

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Is There a Limit to How Many Balls You Can Juggle?
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Carl Court, Getty Images

In 2017, a juggler named Alex Barron broke a record when he tossed 14 balls into the air and caught them each once. The feat is fascinating to watch, and it becomes even more impressive once you understand the physics behind it.

As WIRED explains in a new video, juggling any more than 14 balls at once may be physically impossible. Researchers who study the limits of juggling have found that the success of a performance relies on a number of different components. Speed, a.k.a. the juggler's capacity to move their hands in time to catch each ball as it lands, is a big one, but it's not the most important factor.

What really determines how many balls one person can juggle is their accuracy. An accurate juggler knows how to keep their balls from colliding in midair and make them land within arm's reach. If they can't pull that off, their act falls apart in seconds.

Breaking a juggling world record isn't the same as breaking a record for sprinting or shot put. With each new ball that's added to the routine, jugglers need to toss higher and move their hands faster, which means their throws need to be significantly more accurate than what's needed with just one ball fewer. And skill and hours of practice aren't always enough; according to expert jugglers, the current world records were likely made possible by a decent amount of luck.

For a closer look at the physics of juggling, check out the video below.

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LaGuardia Airport Is Serving Up Personalized Short Stories to Passengers
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In between purchasing a neck pillow and a bag full of snacks, guests flying out of the Marine Air Terminal at New York City's LaGuardia Airport can now order up an impromptu short story. As Hyperallergic reports, Landing Pages is an art project that connects writers to travelers looking for short fiction written in the time it takes to reach their destination.

The kiosk was set up as part of the ArtPort Residency, a new collaboration between the Queens Council on the Arts and the Port Authority of New York and New Jersey, which sponsors different art projects at the Marine Air Terminal for a few months at a time.

Artists Lexie Smith and Gideon Jacobs set up the inaugural project at the terminal earlier this month. To request a story from Landing Pages, travelers can visit the kiosk and leave their flight number and contact information. While the passenger is in the air, Smith and Jacobs churn out a custom story, in the form of poetry, illustration, or prose, from their airport terminal workspace and send it out in time for it to reach the reader's phone before he or she lands.

The word count depends on the duration of the flight, and the subject matter often touches upon themes of travel and adventure. As Smith and Jacobs continue their residency through June 30, the pieces they complete will be made available at Landingpages.nyc and in hard copy form at the airport kiosk.

Landing Pages isn't the first airport service to offer à la carte short stories. In 2011, a French startup debuted its short story-dispensing vending machine at Paris's Charles de Gaulle Airport. Those stories come in three categories—one-minute, three-minute, and five-minute reads—and are printed out immediately so travelers can read them during their flight.

[h/t Hyperallergic]

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