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On Music: the flute solo in Debussy's L'après-midi d'un faune

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Earlier this week, I introduced you to the woodwinds via a wonderful Mozart piece, yet one which didn't include one very important instrument: the flute. So I thought I'd spend the entire post today making amends. Of course, the flute (and its predecessor) is one of the oldest instruments in the world, appearing first around 4,000 B.C. made out of bones, hooves, and horns. The Greek God, Pan, the faun (half-man half-goat), is said to have invented the panpipe—a sensual kind of flute—when the nymph he loved was turned into a reed.

From those early wooden flutes, the instrument developed and eventually, through the 19th century "German flute," evolved into the sleek silver version we use today. One of the most famous orchestral pieces featuring the instrument (and another personal fav, by the way) was written by Claude Debussy for Diaghilev's famous Ballets Russes in Paris and premiered there in 1912.


As Diaghilev was want to do, the ballet brought some of the most talented artists together in collaboration, all commissioned to compose a piece inspired by the sensual poetry of L'après-midi d'un faune (The Afternoon of a Faun) by Stéphane Mallarmé. Nijinsky did the choreography and danced the role of the faun, creating one of the biggest scandals of Paris that year.
In the newspaper Le Figaro editor Gaston Calmette wrote: "We have had a faun, incontinent, with vile movements of erotic bestiality and gestures of heavy shamelessness." In reply, the sculptor Auguste Rodin published a defense of the choreography and in a letter to Le Figaro painter Odilon Redon expressed the wish that his friend Mallarmé could have seen "this wonderful evocation of his thought."

Listen to an excerpt from Debussy's Afternoon of a Faun
nijinsky.jpgAnd while the closing "masturbation scene" still draws a lot of interest, ultimately, it's Debussy's gorgeous music that's carried this "Faun" into the 21st century. The opening excerpt here is all flute, sensual and seductive, as Nijinsky and Diaghilev wanted it, and, I'll agree with Redon there - Mallarmé probably would have loved it"¦


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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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