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Dreaming of Peace: Diego Rivera

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Tomorrow is the little-known holiday National Dance Day, which coincides with this week's observance of National Dance Week. Today then is a good day to feature Diego Rivera (1886-1957) and his "Baile en Tehauntepec." The Mexican artist, who was born Diego María de la Concepción Juan Nepomuceno Estanislao de la Rivera y Barrientos Acosta y Rodríguez, was requested by reader AMT.

1. In America, Diego Rivera is known for his 1933 mural for Rockefeller Center, "Man at the Crossroads." Rivera was friendly with the Rockefeller family, which led to his commission, but he upset them (and much of the press and public) by his inclusion of Vladimir Lenin in the painting. He was ordered to stop painting and the mural was hidden from the public; it was chipped off the wall on February 9, 1934. Later, Rivera created a variation of the mural in Mexico City's Palace of Fine Arts with the new title, "Man, Controller of the Universe." He reportedly included a portrait of John D. Rockefeller at a nightclub, with "syphilis bacteria floating above his head."

2. As a child, Rivera was nicknamed "the engineer" for his fascination with trains and other machines. This interest is reflected in some of his works, most notably his Detroit Industry frescoes in the Detroit Institute of Arts. Commissioned by the Fords, the paintings depict U.S. industrial life, with a focus on Detroit's car plant workers. Although Rivera considered it the most successful work of his career, the local newspaper did not react very favorably: they described the works as "coarse in conception"¦ foolishly vulgar"¦ a slander to Detroit workmen"¦" and even "un-American." Henry Ford's son Edsel replied to the controversy with the simple statement, "I admire Rivera's spirit. I really believe he was trying to express his idea of the spirit of Detroit.

3. One of Rivera's last works, the 1952 painting "Nightmare of War, Dream of Peace," disappeared more than 50 years ago, an incredible feat since the mural is 40 feet long by 10 feet high. The Mexican government had asked Rivera to produce a work to represent Mexico at a global exhibition, a request Rivera accepted, saying he would paint a mural "dedicated to peace." His final product depicts "a benevolent Mao and Stalin" attempting to reach a peace agreement with "a sour-looking Uncle Sam" flanked by representatives from England and France. The government refused to exhibit the work due to its anti-American theme. The work is rumored to have been given to Mao by Rivera in the 1950s and then to have been destroyed by Mao, though other rumors place it in Moscow or Poland.

4. Rivera was a bit of a ladies' man. He married four times, to three different women. (He married Frida Kahlo twice.) One of his long-term lovers is sometimes also referred to as his common-law wife. With his wives and lovers, he fathered several children, and supposedly abandoned all of them. His marriage to Frida Kahlo, about 20 years his junior, gained him the most notoriety, though. Rivera is often said to have been abusive to Frida; he himself stated, "If I ever loved a woman, the more I loved her, the more I wanted to hurt her. Frida was only the most obvious victim of this disgusting trait." Yet one of Rivera's children, Guadalupe, refutes the claims her father was abusive, stating, "It has been said that my father made Frida suffer and I can tell you"¦ Frida made my father suffer."

A larger version of "Baile en Tehauntepec" is available here.

Fans should check out Rivera's autobiography; the Diego River virtual museum; the collection of his work on Art in the Picture; the Diego Rivera Mural Project; the Cubist Paintings of Diego Rivera exhibition at NGA; Kahlo's portrait of Rivera and his cover on TIME magazine; this photo of Rivera and Amelia Earhart; Rupert Garcia on Rivera and Kahlo (video); image galleries from The New York Times and NPR; and, for teachers, a Rivera curriculum guide and Web activity.

"Feel Art Again" appears every Tuesday, Thursday, and Saturday. You can e-mail us at feelartagain@gmail.com with details of current exhibitions, for sources or further reading, or to suggest artists.

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iStock // Ekaterina Minaeva
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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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8 Common Dog Behaviors, Decoded
May 25, 2017
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Dogs are a lot more complicated than we give them credit for. As a result, sometimes things get lost in translation. We’ve yet to invent a dog-to-English translator, but there are certain behaviors you can learn to read in order to better understand what your dog is trying to tell you. The more tuned-in you are to your dog’s emotions, the better you’ll be able to respond—whether that means giving her some space or welcoming a wet, slobbery kiss. 

1. What you’ll see: Your dog is standing with his legs and body relaxed and tail low. His ears are up, but not pointed forward. His mouth is slightly open, he’s panting lightly, and his tongue is loose. His eyes? Soft or maybe slightly squinty from getting his smile on.

What it means: “Hey there, friend!” Your pup is in a calm, relaxed state. He’s open to mingling, which means you can feel comfortable letting friends say hi.

2. What you’ll see: Your dog is standing with her body leaning forward. Her ears are erect and angled forward—or have at least perked up if they’re floppy—and her mouth is closed. Her tail might be sticking out horizontally or sticking straight up and wagging slightly.

What it means: “Hark! Who goes there?!” Something caught your pup’s attention and now she’s on high alert, trying to discern whether or not the person, animal, or situation is a threat. She’ll likely stay on guard until she feels safe or becomes distracted.

3. What you’ll see: Your dog is standing, leaning slightly forward. His body and legs are tense, and his hackles—those hairs along his back and neck—are raised. His tail is stiff and twitching, not swooping playfully. His mouth is open, teeth are exposed, and he may be snarling, snapping, or barking excessively.

What it means: “Don’t mess with me!” This dog is asserting his social dominance and letting others know that he might attack if they don’t defer accordingly. A dog in this stance could be either offensively aggressive or defensively aggressive. If you encounter a dog in this state, play it safe and back away slowly without making eye contact.

4. What you’ll see: As another dog approaches, your dog lies down on his back with his tail tucked in between his legs. His paws are tucked in too, his ears are flat, and he isn’t making direct eye contact with the other dog standing over him.

What it means: “I come in peace!” Your pooch is displaying signs of submission to a more dominant dog, conveying total surrender to avoid physical confrontation. Other, less obvious, signs of submission include ears that are flattened back against the head, an avoidance of eye contact, a tongue flick, and bared teeth. Yup—a dog might bare his teeth while still being submissive, but they’ll likely be clenched together, the lips opened horizontally rather than curled up to show the front canines. A submissive dog will also slink backward or inward rather than forward, which would indicate more aggressive behavior.

5. What you’ll see: Your dog is crouching with her back hunched, tail tucked, and the corner of her mouth pulled back with lips slightly curled. Her shoulders, or hackles, are raised and her ears are flattened. She’s avoiding eye contact.

What it means: “I’m scared, but will fight you if I have to.” This dog’s fight or flight instincts have been activated. It’s best to keep your distance from a dog in this emotional state because she could attack if she feels cornered.

6. What you’ll see: You’re staring at your dog, holding eye contact. Your dog looks away from you, tentatively looks back, then looks away again. After some time, he licks his chops and yawns.

What it means: “I don’t know what’s going on and it’s weirding me out.” Your dog doesn’t know what to make of the situation, but rather than nipping or barking, he’ll stick to behaviors he knows are OK, like yawning, licking his chops, or shaking as if he’s wet. You’ll want to intervene by removing whatever it is causing him discomfort—such as an overly grabby child—and giving him some space to relax.

7. What you’ll see: Your dog has her front paws bent and lowered onto the ground with her rear in the air. Her body is relaxed, loose, and wiggly, and her tail is up and wagging from side to side. She might also let out a high-pitched or impatient bark.

What it means: “What’s the hold up? Let’s play!” This classic stance, known to dog trainers and behaviorists as “the play bow,” is a sign she’s ready to let the good times roll. Get ready for a round of fetch or tug of war, or for a good long outing at the dog park.

8. What you’ll see: You’ve just gotten home from work and your dog rushes over. He can’t stop wiggling his backside, and he may even lower himself into a giant stretch, like he’s doing yoga.

What it means: “OhmygoshImsohappytoseeyou I love you so much you’re my best friend foreverandeverandever!!!!” This one’s easy: Your pup is overjoyed his BFF is back. That big stretch is something dogs don’t pull out for just anyone; they save that for the people they truly love. Show him you feel the same way with a good belly rub and a handful of his favorite treats.

The best way to say “I love you” in dog? A monthly subscription to BarkBox. Your favorite pup will get a package filled with treats, toys, and other good stuff (and in return, you’ll probably get lots of sloppy kisses). Visit BarkBox to learn more.

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