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Magazine Sneak Peek: A Joyous History of Toilet Paper

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In this month's new issue (hitting stands next week!), Linda Rodriguez has written a genius piece on the America's greatest invention: toilet paper. It's a fascinating story, but you don't have to take our word for it. Here's just a brief and incomplete that we included as a sidebar. Enjoy!

Great Moments in Toilet Paper History

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* Ever ahead of the curve, the Chinese begin wiping with scraps of rice paper as far back as the 6th century. In the 14th century, the Bureau of Imperial Supplies commissions 2 ft. by 3 ft. sheets for the emperor's personal use.

*In 1532, French writer François Rabelais satirizes financial excess with characters who brag about the joys of wiping with the neck of a "well-downed goose." Rabelais' exaggerations aside, the French do take their toilet solutions seriously. French royalty and persons of wealth allegedly begin using lace scented with rose or lavender water.

*The New York Times prints the phrase "toilet paper" for the first time in 1888. The article covers a hazing scandal at the U.S. Naval Academy where some cadets forced others to "chew their toilet paper." No mention of whether said toilet paper had been already used.

*A 1935 advertisement for Northern Tissue touts the product's "splinter-free" superiority. Most toilet paper at the time is uncomfortable (if not painful), owing to a less-fine milling process.
*Though initially slow to embrace toilet paper, the English contribute to its evolution in 1942, when St. Andrew's Paper Mill invents two-ply.

tpsign.jpg*In some countries, buying toilet paper is still considered flushing your money down the toilet—most literally in Zimbabwe, where inflation has reached an astronomical 234 million percent. There, it's cheaper, per sheet, to wipe with a 1,000-dollar Zimbabwe note than with toilet paper. Worse still, the currency wreaks havoc on plumbing systems. The notes have caused so much damage that some public toilets bear signs saying "No Zim Dollars."

*Japan releases another potty-related invention in 1997, the mock flusher. Because natural restroom sounds are a source of shame in Japan, people in public stalls often cover up the noise by flushing the toilet several times during the act. Concerns about water waste led to the invention of the mock flusher, which simulates the sound of flushing without actually letting water go down the drain.

But that just scratches the surface! Curious what else is in the magazine? Then pick up the new issue of mental_floss magazine here. Or take advantage of our latest offer and pick up a t-shirt with your subscription for just a couple of dollars more. 

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iStock // Ekaterina Minaeva
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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Name the Author Based on the Character
May 23, 2017
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