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How Rain Helped the Mongols Conquer Asia

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In the early 1200s, Genghis Khan united the warring Mongolian tribes into a mobile, efficient military state. Lashing outward in all directions from their home on Central Asia's steppe, the Mongolian armies conquered a large swath of Central Asia in just a few decades. The empire continued to expand under Genghis Khan's descendants and, at its height, was one of the largest in human history, extending from Asia's Pacific coast to Central Europe.

The Great Khan is remembered as a politically savvy leader and a brilliant military tactician, but the rise of his empire, new research suggests, might have also had something to do with a stretch of unusually nice weather.

In 2010, American researchers Neil Pederson and Amy Hessl were in Mongolia's Khangai Mountains, studying the impact of climate change on the country's wildfires. As they drove past an old flow of now-solid lava left by a volcanic eruption thousands of years ago, they saw stands of stunted pine trees growing out of cracks in the lava.

Now, as any budding naturalist can tell you, the annual growth rings of many trees reflect the conditions they grew in. A long, wet growing season results in a wide ring, and a drought-stricken year means a thin ring. After you figure out the age of a tree, these growth patterns can provide a year-by-year record of what the local climate was like. Luckily for Pederson and Hessl, these patterns were written very clearly into the trunks of their Siberian pines, which were well-preserved by the cold, dry conditions of the steppe. The pair had potentially found a wooden record of climate conditions going back thousands of years.

Pederson and Hessl took samples from 17 of the trees and found that they were indeed very old. The innermost rings of some them dated all the way back to the 7th century. Since this discovery, they've gone back and sampled more than a hundred trees in the mountains and the Orkhon Valley region, where Genghis Khan established the seat of his growing empire.

Combining their tree-growth patterns with temperature reconstructions, Pederson, Hessl, and their team pieced together a picture of what the climate was like during the centuries that the Mongols conquered and ruled.

Just before Genghis Khan rose to power, Mongolia's climate was harsh, both physically and politically. The Mongolian tribes warred against each other, and the steppe was cold and stricken by drought. Amid the conflict, the researchers say, the worsening dry conditions of the land could have been an important factor in the collapse of the old order, and paved the way for centralized leadership under Genghis Khan. "What might have been a relatively minor crisis instead developed into decades of warfare and eventually produced a major transformation of Mongol politics," they write.

Then, in the early 13th century, as Genghis Khan unified the tribes, the droughts gave way to a period when the steppes were wetter and warmer than they'd ever been. "This period, characterized by 15 consecutive years of above average moisture in central Mongolia and coinciding with the rise of Genghis Khan, is unprecedented over the last 1,112 years," the researchers say. In addition to being wet, Mongolia at the time was warm, but not exceptionally hot.

In these conditions the Mongolian grasslands would have flourished, providing fuel for the Mongolian war machine. Each of Genghis Khan's mounted warriors used several horses, and the conquering armies brought herds of livestock with them for food and other resources. The dramatic shift in temperature and precipitation came at the perfect time to provide resources for rapid military mobilization and the Mongols' early expansion.

After the empire's initial spasms of growth, the tree ring and temperature data show a return to a cold, dry climate. By then, though, the Mongols had defeated several other Central Asian powers and could exploit the conquered regions instead of relying on the grass of the steppes and their local resources.

The climate shift certainly isn't the only driver of the empire's quick rise; it might have also just been coincidental, the researchers say. To flesh out the picture that the tree rings provide, the team is working on several other studies that could corroborate their ideas. Ecologist Hanqin Tian is developing models to connect the dots between the tree-ring records of weather and grass production. Biologist Avery Cook Shinneman will analyze the layers of fungal spores from animal dung that are trapped in sediment in Mongolian lakes, which could indicate the abundance of the Mongols' livestock. Meanwhile, historian Nicola Di Cosmo will comb through records from Asia and Europe looking for historical references to the climate and the strength of the Mongolian armies.

While the tree rings provide clues about the past climate and its possible influence on the rise of an empire, they also hint that another major shake-up is yet to come in Central Asia. As they did hundreds of years ago, conditions in the region have turned from wet to arid, with long, cold winters and drought-stricken summers comparable to those experienced just before Genghis Khan seized power. During the 2000s, livestock booms went bust; millions of animals died, and hundreds of thousands of displaced herders flocked to the city of Ulaanbaatar.

Those earlier droughts happened in a much cooler climate, though. Central Asia is currently warming more than the global average, and the combination of rising temperatures and droughts, the researchers warn, could mean another era of climate-spurred social and political upheaval.

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iStock // Ekaterina Minaeva
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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© Nintendo
Nintendo Will Release an $80 Mini SNES in September
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© Nintendo

Retro gamers rejoice: Nintendo just announced that it will be launching a revamped version of its beloved Super Nintendo Classic console, which will allow kids and grown-ups alike to play classic 16-bit games in high-definition.

The new SNES Classic Edition, a miniature version of the original console, comes with an HDMI cable to make it compatible with modern televisions. It also comes pre-loaded with a roster of 21 games, including Super Mario Kart, The Legend of Zelda: A Link to the Past, Donkey Kong Country, and Star Fox 2, an unreleased sequel to the 1993 original.

“While many people from around the world consider the Super NES to be one of the greatest video game systems ever made, many of our younger fans never had a chance to play it,” Doug Bowser, Nintendo's senior vice president of sales and marketing, said in a statement. “With the Super NES Classic Edition, new fans will be introduced to some of the best Nintendo games of all time, while longtime fans can relive some of their favorite retro classics with family and friends.”

The SNES Classic Edition will go on sale on September 29 and retail for $79.99. Nintendo reportedly only plans to manufacture the console “until the end of calendar year 2017,” which means that the competition to get your hands on one will likely be stiff, as anyone who tried to purchase an NES Classic last year will well remember.

In November 2016, Nintendo released a miniature version of its original NES system, which sold out pretty much instantly. After selling 2.3 million units, Nintendo discontinued the NES Classic in April. In a statement to Polygon, the company has pledged to “produce significantly more units of Super NES Classic Edition than we did of NES Classic Edition.”

Nintendo has not yet released information about where gamers will be able to buy the new console, but you may want to start planning to get in line soon.