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$50 Challenge Winner!

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On January 25, we announced a $50 challenge. We made up a 10-question challenge based on information in the January/Febuary 2009 issue of mental_floss magazine; the goal was to be the first reader to submit the correct (as found in the magazine) answers for all 10 questions.

The Winner

"Ben Linus" got all 10 correct answers to us at 1:43 p.m., a mere 13 minutes after the challenge was posted! Congratulations! (We'll be in touch via e-mail about your prize.)

Check out the winning answers, and some inventive guesses, after the jump.

The Answers

1. The death of what actor caused "worldwide hysteria" and "several suicides," as well as attracting a line of mourners that stretched for 11 blocks?
A. Rudolph Valentino (page 70)
Inventive guess: Heath Ledger

2. "Girls don't dream about the circus"¦ they dream dirty dreams," according to what choreographer?
A. Agness de Mille (page 27)

3. Of the many animal-inspired dances, which one was so scandalous it landed an "unfortunate young lady in New Jersey" a jail term?
A. The Turkey Trot (page 19)

4. "Welcome to the Jungle" roared over the loudspeakers to blast what dictator out of hiding?
A. Manuel Noriega (page 15)

5. In the treaty between Cuba and America enabling American military use of Guantanamo Bay, what little detail in the fine print prevents Cuba from evicting us?
A. The agreement can only be terminated through mutual consent from both countries (page 46)

6. Hails of arrows have prevented documentary crews, governments, fishermen, and rescue crews from getting anywhere near what unexplored territory?
A. North Sentinel Island, in the Bay of Bengal, which is technically part of India (page 42)

7. According to Andy Davis, mental_floss has come pretty far since its beginnings at Duke. Just how far, geographically speaking, has it gone?
A. Bagram Airbase, Afghanistan, which one entrant pointed out is approximately 7100 miles (page 9)
Popular guesses: 544 miles (the distance from Duke to the m_f address in Novelty, OH); 529 miles (the distance from Duke to the m_f address in Birmingham, AL)
Inventive guesses: 400 miles; 886 miles (the distance from Duke to Mount Morris, IL); 399 miles ("as the crow flies" from Duke to the OH m_ office)

8. What previous economic crisis was referred to as the "Great Epizootic"?
A. The panic of 1873 / equine influenza (page 36)

9. Which sport was designed for "businessmen who found the new game of basketball too vigorous"?
A. Volleyball (page 70)

10. Five years after a study by RAND into the effectiveness of free health care, what percentage of medical plans had deductibles?
A. More than 90 percent (page 54)
Popular guess: 30 percent

And if you STILL don't have a copy of that issue, you can purchase it here.

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iStock // Ekaterina Minaeva
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
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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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iStock
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Why Your iPhone Doesn't Always Show You the 'Decline Call' Button
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iStock

When you get an incoming call to your iPhone, the options that light up your screen aren't always the same. Sometimes you have the option to decline a call, and sometimes you only see a slider that allows you to answer, without an option to send the caller straight to voicemail. Why the difference?

A while back, Business Insider tracked down the answer to this conundrum of modern communication, and the answer turns out to be fairly simple.

If you get a call while your phone is locked, you’ll see the "slide to answer" button. In order to decline the call, you have to double-tap the power button on the top of the phone.

If your phone is unlocked, however, the screen that appears during an incoming call is different. You’ll see the two buttons, "accept" or "decline."

Either way, you get the options to set a reminder to call that person back or to immediately send them a text message. ("Dad, stop calling me at work, it’s 9 a.m.!")

[h/t Business Insider]

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