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Explaining the Chinese Zodiac (Just in Time for Chinese New Year)

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According to legend, the celebration of the Chinese New Year began with a monster called Nian. The beast would arrive on the first day of the new year and devour crops, livestock and people. To protect themselves, people put food outside their doors, hoping that Nian wouldn't attack after eating. They also used firecrackers to scare it away. One year, Nian was driven from a village by a child wearing red clothes, so people began hanging red lanterns and scrolls on their windows and doors when a new year began—and Nian never returned. (Nian was eventually captured by Hongjunlaozu, a Taoist monk, and became his mount.)

Today, the Chinese New Year is celebrated with a festival that begins on the first day of the first lunar month in the Chinese calendar and ends on the fifteenth day (at least since the Han Dynasty—before that, dynasties celebrated during the twelfth, eleventh or tenth months). The Nian legend explains the food, the lanterns and the fireworks that we associate with the holiday, but I'm sure I'm not the only person who knows his Chinese zodiac sign, but doesn't know story behind it. Let's fix that.

What's your sign? (And what are the signs?)

While we have a linear concept of time in the West, the traditional Chinese calendar is cyclical and based on the cycles of the moon (China has used the Western calendar since 1911, but the lunar version is still used for holidays and festive occasions). A folk method for keeping track of the years is the twelve animal signs. Each year is assigned an animal according to this cycle: Rat, Ox, Tiger, Rabbit, Dragon, Snake, Horse, Sheep (or Ram), Monkey, Rooster, Dog, and Boar (or Pig).

In addition to the 12-year animal zodiac, there's a 10-year cycle of ten "heavenly stems" composed of the five elements (Wood, Fire, Earth, Metal and Water) in their alternating yin and yang forms. Together, they form a 60-year cycle that begins with Yang Wood Rat and ends with Yin Water Boar. The last cycle began in 1984 and will end in 2044. Today, we enter the 26th year of the cycle—Yin Earth Ox.

Why are the animals in that order?

According to Chinese legend, when the system was created, thirteen animals argued about who got to be first in the cycle of years. The gods (or the Jade Emperor or the Buddha, depending on where you hear the story) decided that a contest was the only fair way to settle the matter. The animals would race across a river and be placed in the cycle in the order that they finished.

zodiac.jpgThe Rat & The Ox: The thirteen animals gathered on one side of the river and jumped in. The rat was a poor swimmer and decided that the best way to cross the river was to ride on the ox's back. The ox—apparently a little naïve—let the rat on board. As soon as the ox crossed the river, the rat jumped off his back and, in a photo finish, touched the shore first.

The Tiger: Not far behind was the tiger, which had a harder time fighting the river's current than the ox, but was just strong enough to come in third.

The Rabbit & The Dragon: The rabbit arrived next, explaining that it planned to cross the river by jumping from one stone to another. Halfway across, though, the rabbit hopped onto a floating log and almost got swept downstream. The log somehow washed up on shore. The dragon, which flew across the river, came in fifth. The gods were curious as to why a mighty flying dragon didn't come in first place. The dragon explained that it had to stop to make rain for the earth. On the way to the finish line, the dragon saw rabbit clinging to a log and decided to do a good deed and blow the log to shore.

The Snake & The Horse: The horse then came galloping up onto the shore, only to be surprised by the sight of the snake, which had hidden itself wrapped around the horse's hoof. The startled horse fell backwards into the river, allowing the snake the sixth spot, while the horse placed seventh.

The Ram, The Monkey & The Rooster: The ram, monkey and rooster came ashore together after helping each other across the river. The rooster spotted a raft at the start of the race and agreed to share if the others rowed. The gods placed them in the order they stepped off the raft.

The Dog & The Pig: The dog, which was supposed to be the best swimmer of the bunch, came in eleventh place. It explained that it was so far behind because it hadn't had a good bath in a while and decided to take one in the river. The pig, which finished last, also got held up when it got hungry during the race and stopped for lunch and a nap.

And the 13th animal that started the race? The cat was also riding on the ox's back, but the rat pushed the cat into the river, costing it a spot in the cycle. This must be why cats don't like rats or water to this day.

Making pigs (and rats and oxen and rams, etc.) of ourselves

Each animal has a distinct personality, and the animal sign a person is born under is believed to bestow upon them certain traits and characteristics. But the animals assigned by year are not the only factor. There are also inner animal signs (representing the person you would like to be) assigned to the month you were born and secret animal signs (representing the side of you hidden from the rest of the world) assigned to the shichen or "large-hour" (two-hour period of the day) during which you were born. I was born in the year of the Rat, but I'm a Dog internally and a Monkey secretly.

If you've got a burning question that you'd like to see answered here, shoot me an email at flossymatt (at) Twitter users can also make nice with me and ask me questions there. Be sure to give me your name and location (and a link, if you want) so I can give you a little shout out.

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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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Cs California, Wikimedia Commons // CC BY-SA 3.0
How Experts Say We Should Stop a 'Zombie' Infection: Kill It With Fire
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Cs California, Wikimedia Commons // CC BY-SA 3.0

Scientists are known for being pretty cautious people. But sometimes, even the most careful of us need to burn some things to the ground. Immunologists have proposed a plan to burn large swaths of parkland in an attempt to wipe out disease, as The New York Times reports. They described the problem in the journal Microbiology and Molecular Biology Reviews.

Chronic wasting disease (CWD) is a gruesome infection that’s been destroying deer and elk herds across North America. Like bovine spongiform encephalopathy (BSE, better known as mad cow disease) and Creutzfeldt-Jakob disease, CWD is caused by damaged, contagious little proteins called prions. Although it's been half a century since CWD was first discovered, scientists are still scratching their heads about how it works, how it spreads, and if, like BSE, it could someday infect humans.

Paper co-author Mark Zabel, of the Prion Research Center at Colorado State University, says animals with CWD fade away slowly at first, losing weight and starting to act kind of spacey. But "they’re not hard to pick out at the end stage," he told The New York Times. "They have a vacant stare, they have a stumbling gait, their heads are drooping, their ears are down, you can see thick saliva dripping from their mouths. It’s like a true zombie disease."

CWD has already been spotted in 24 U.S. states. Some herds are already 50 percent infected, and that number is only growing.

Prion illnesses often travel from one infected individual to another, but CWD’s expansion was so rapid that scientists began to suspect it had more than one way of finding new animals to attack.

Sure enough, it did. As it turns out, the CWD prion doesn’t go down with its host-animal ship. Infected animals shed the prion in their urine, feces, and drool. Long after the sick deer has died, others can still contract CWD from the leaves they eat and the grass in which they stand.

As if that’s not bad enough, CWD has another trick up its sleeve: spontaneous generation. That is, it doesn’t take much damage to twist a healthy prion into a zombifying pathogen. The illness just pops up.

There are some treatments, including immersing infected tissue in an ozone bath. But that won't help when the problem is literally smeared across the landscape. "You cannot treat half of the continental United States with ozone," Zabel said.

And so, to combat this many-pronged assault on our wildlife, Zabel and his colleagues are getting aggressive. They recommend a controlled burn of infected areas of national parks in Colorado and Arkansas—a pilot study to determine if fire will be enough.

"If you eliminate the plants that have prions on the surface, that would be a huge step forward," he said. "I really don’t think it’s that crazy."

[h/t The New York Times]