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The Week in Review (Plus Some Weekend Nonsense & a T-Shirt Giveaway)

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In case you weren't glued to this site all week, consider this your make-up class. Here's a look back at some of the wonderful topics we've recently covered:

"¢ 7 Pampered Celebrities and their Ridiculous Pre-show Demands

"¢ Manly Ways to Prepare Turkey

"¢ 7 Insane Food Competitions

"¢ Famous Last Words: The Animated Musical

"¢ When Sitcom Stars Start Expecting

"¢ Stuff You Don't Know About Writers You Might

"¢ The Monster of the Andes, The Meanest Man in America, and 7 other Prolific Serial Killers

Read on for more of this week's best posts, plus the aforementioned weekend nonsense and a chance to win a t-shirt!

Absinthe Comes to America

"¢ The First Time News Was Fit To Print: Golden Gate Bridge, Bill Maher, Toyota Prius

"¢ (Way More Than) Everything You Wanted to Know about Guinea Pigs

"¢ The Life and Times of Gary Larson

Dumpster Diving

"¢ Nine Holiday Gifts that Send a Message

Feel Art Again. And Again.

"¢ Why the Farm Bill is Cool

Brand Affinities

"¢ Eat Like the Pilgrims

"¢ Quizzes: Nintendo History, Transient Sports Franchises, Inventions Timeline and Opening Lyrics

And here now the nonsense: How long do you think it takes for toothpaste to fall off the brush?


At 11:30am Eastern Time this morning (and 59 seconds), I (Jason) stood my Braun Professional Care electric toothbrush upright. At what time will the toothpaste become unstuck and reach the strategically placed Post-it Note waiting below?


A couple of things to consider:

1) After taking this picture, I relocated the toothbrush to the top of my dresser. Laptop heat is not a factor.

2) The toothpaste is Crest Sensitivity.

We'll play Price is Right rules. The person who comes closest to the actual time of toothpaste/toothbrush separation without going over wins a free mental_floss t-shirt. You can guess up to five times, but they all must be in separate comments. Keep those guesses in Eastern Time. And be sure to mention which shirt you're playing for. Like this:

Comment #1: Jason
Saturday, 11:33am
Rhesus shirt, Large

Since there's nothing more boring than thinking about someone watching toothpaste, scroll back up and read a few of this week's greatest hits. I'll post the winning time tomorrow. Best of luck.

UPDATE: Sunday, 11:52pm

Around 3pm Saturday, I moved the toothbrush back to its bathroom base. (Around 2:59pm, this was what my wife said: "Seriously, get the toothbrush out of here.") All afternoon, the increasingly solid Crest Sensitivity toothpaste clung admirably to the bristles. But after an intense evening walking of the dog, I chose to shower up. I like my showers hot. And the steam hot showers produce does wonders for crusty globs of toothpaste. While toweling off, I noticed the toothpaste had fallen, the contest over. It was 10:38pm. Looks like Sarah's guess "“ 10:04pm "“ is the winner! We'll be in touch about your t-shirt. Congratulations!

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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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Stephen Missal
New Evidence Emerges in Norway’s Most Famous Unsolved Murder Case
May 22, 2017
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A 2016 sketch by a forensic artist of the Isdal Woman
Stephen Missal

For almost 50 years, Norwegian investigators have been baffled by the case of the “Isdal Woman,” whose burned corpse was found in a valley outside the city of Bergen in 1970. Most of her face and hair had been burned off and the labels in her clothes had been removed. The police investigation eventually led to a pair of suitcases stuffed with wigs and the discovery that the woman had stayed at numerous hotels around Norway under different aliases. Still, the police eventually ruled it a suicide.

Almost five decades later, the Norwegian public broadcaster NRK has launched a new investigation into the case, working with police to help track down her identity. And it is already yielding results. The BBC reports that forensic analysis of the woman’s teeth show that she was from a region along the French-German border.

In 1970, hikers discovered the Isdal Woman’s body, burned and lying on a remote slope surrounded by an umbrella, melted plastic bottles, what may have been a passport cover, and more. Her clothes and possessions were scraped clean of any kind of identifying marks or labels. Later, the police found that she left two suitcases at the Bergen train station, containing sunglasses with her fingerprints on the lenses, a hairbrush, a prescription bottle of eczema cream, several wigs, and glasses with clear lenses. Again, all labels and other identifying marks had been removed, even from the prescription cream. A notepad found inside was filled with handwritten letters that looked like a code. A shopping bag led police to a shoe store, where, finally, an employee remembered selling rubber boots just like the ones found on the woman’s body.

Eventually, the police discovered that she had stayed in different hotels all over the country under different names, which would have required passports under several different aliases. This strongly suggests that she was a spy. Though she was both burned alive and had a stomach full of undigested sleeping pills, the police eventually ruled the death a suicide, unable to track down any evidence that they could tie to her murder.

But some of the forensic data that can help solve her case still exists. The Isdal Woman’s jaw was preserved in a forensic archive, allowing researchers from the University of Canberra in Australia to use isotopic analysis to figure out where she came from, based on the chemical traces left on her teeth while she was growing up. It’s the first time this technique has been used in a Norwegian criminal investigation.

The isotopic analysis was so effective that the researchers can tell that she probably grew up in eastern or central Europe, then moved west toward France during her adolescence, possibly just before or during World War II. Previous studies of her handwriting have indicated that she learned to write in France or in another French-speaking country.

Narrowing down the woman’s origins to such a specific region could help find someone who knew her, or reports of missing women who matched her description. The case is still a long way from solved, but the search is now much narrower than it had been in the mystery's long history.

[h/t BBC]