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FREE Magazine Subscription with Purchase of our New Book!

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It's the greatest deal in the history of history books! Our first hardback, The Mental Floss History of the World: An Irreverent Romp Through History's Best Bits, hits stores later this month and we're so excited that we've teamed up with the fine folks at Amazon.com to give you a special deal. Pre-order the book before October 28th and we'll throw in 6 FREE MONTHS of mental_floss magazine!


Just CLICK HERE to get the deal now.


Of course, with a special this special, you might have questions. Like: Can you add the free subscription to your existing subscription? Can you keep the book but send the subscription to a friend? Are we the nicest magazine ever? The short answer to all of these is yes; longer answers are below. Be sure to order today before the deal disappears"¦

THE FAQ

Can I add the 6-month free subscription to my existing subscription?

Yes! We'll happily tack on 6 free months (3 additional issues) to your current subscription. Once you've bought the book and clicked for the deal at Amazon, you'll be signed up. On November 1st, you'll get an e-mail from Amazon with a special code to redeem your 6-month subscription.  Simply make sure that you enter your name and address EXACTLY as it appears on your magazine's mailing label, and it will get added to your current subscription.

Can I keep the book, but send the subscription to a friend, or vice versa?

Yes! Amazon makes this easy. Simply send the book wherever you'd like (keep it, or send it to someone else). Then, once Amazon mails you the special code, just specify where you'd like to send the subscription. If you want to send it to a friend, feel free. If you'd like to hoard both, you're more than welcome to do that, too.

Can I see inside this book?

Yes! HarperCollins is making it simple. Just click here to get a sneak peek.

Does this free magazine deal apply only to U.S. subscriptions?

Yes. Unfortunately, we can only send the free subscriptions to addresses within the United States.

Does this deal really end on October 28th?

Sadly, yes. This whopper of a deal only applies to pre-orders.

Do you have any History of the World content at mentalfloss.com for me to peruse?

Yes! Every day in October we'll be highlighting fascinating content from the book and creating fun quizzes to help you love history as much as we do. Just look for it here.

Is mental_floss magazine really that good?

Picture 5.pngYes! Newsweek calls it "A smart (-alecky) read." The Washington Post calls it "delightfully eccentric and eclectic." And it's been praised everywhere from the LA Times to the Wall Street Journal. This year we've tackled How to Get into Heaven (a travel guide for the afterlives of various religions), The Secret Lives of Presidents (who knew that Nixon proposed to his wife on their first meeting, then drove her around on dates with other people for the next few years?), and The Search for the Next Einstein (mind-blowing inventions from the world's best scientists). And all that's coupled with fascinating science stories, incredible bios, evocative arts features, and a spinning the globe section that's chock full of lush photos and vivid travel stories. If you love to learn, this magazine's made for you.

And if I have other questions?

Yes, we figured you might! Just write us at sixmonthsfree@mentalfloss.com, and we'll get right back to you.

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iStock // Ekaterina Minaeva
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technology
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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technology
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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