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How Do Fire Eaters Eat Fire?

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Very carefully. No, I'm not being a smart aleck; fire eaters, from fakirs to sideshow performers, have very few secrets about their craft. Urban legend has it that fire eaters use "cold flames" that aren't hot enough to burn the skin or coat their mouths with fireproofing chemicals, but any flame from any source is hot enough to burn the mouth (how many times have you burned the roof of your mouth on something as innocent as piece of pizza?) and applying flame-retarding chemicals to the mouth can pose health risks. The tricks of the trade are precision, practice and the knowledge of one simple law—heat travels upward.

[A quick disclaimer: I am not a fire eater, and this is not a fire-eating lesson. I am a writer, and this is an explanation of how professional fire eaters do what they do. You should not use this article to practice fire-eating at home, and if you do, you cannot blame me or mentalfloss.com when your spouse/significant other/roommate/landlord/legal guardian asks you how you burned the place down. Now then"¦]

Eat Up

Fire eaters don't literally eat fire. They place flames in their mouth and extinguish them. It's like snuffing out a candle with your hand, but more impressive. During their performance, the fire eater has to remember two things: one, fire and hot air move upward, and two, don't inhale.

fire-eater2.jpgA fire-eater starts by taking a wide stance to keep her* balance and tilting her head back while holding the torch above.


As she lowers the torch towards her mouth, the fire eater takes a deep breath and begins to exhale slow and steady. This slow exhalation keeps the heat away from the fire eater's face as she moves the torch closer to her face and places it in her mouth. With her tongue stuck out wide and flat, the fire eater places the wick of the torch (which should be cool to the touch—fire eaters often use Kevlar thread for their wicks) onto it and partially closes her lips around the torch in an "O" shape.

So far, so good. Now the fire eater has to extinguish the flame, and quick. There are two ways to do this. The fire eater can completely close her lips all the way around the torch, cutting off oxygen and killing the flame, or she can put the flame out with a quick exhaling breath. The second method is preferable for performances where the torch has been lit for a while and may be too hot to touch with the lips.

That's fire eating in a nutshell (though fire eaters have a number of other tricks in their repertoires, like vapor tricks, multiple torch eats and fancy extinguishes). It seems pretty basic, but to do it right and make it look good for a crowd, fire eaters learn the method and then spend years practicing. If this sounds like the kind of thing you want to make a career or a hobby out of, the Coney Island Sideshow School offers classes in the art of fire eating.

* I'm going with the feminine pronoun because 1. most of the fire eaters I've seen in my day have been women and 2. I don't feel like writing he/she every time.

This question was asked by reader Katie Sue. If you've got a burning question that you'd like to see answered here, shoot me an email at flossymatt (at) gmail.com. Twitter users can also make nice with me and ask me questions there. Be sure to give me your name and location (and a link, if you want) so I can give you a little shout out.

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iStock // Ekaterina Minaeva
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Opening Ceremony
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These $425 Jeans Can Turn Into Jorts
May 19, 2017
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Opening Ceremony

Modular clothing used to consist of something simple, like a reversible jacket. Today, it’s a $425 pair of detachable jeans.

Apparel retailer Opening Ceremony recently debuted a pair of “2 in 1 Y/Project” trousers that look fairly peculiar. The legs are held to the crotch by a pair of loops, creating a disjointed C-3PO effect. Undo the loops and you can now remove the legs entirely, leaving a pair of jean shorts in their wake. The result goes from this:

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Opening Ceremony

To this:

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Opening Ceremony

The company also offers a slightly different cut with button tabs in black for $460. If these aren’t audacious enough for you, the Y/Project line includes jumpsuits with removable legs and garter-equipped jeans.

[h/t Mashable]

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