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On Music: Prokofiev's Romeo and Juliet

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Sergei Prokofiev was one of those precocious Mozartian geniuses, composing his first piece at the age of five and his first opera at the age of seven. He also mastered chess early on and I think even went on to compete against some heavy-duty Russian world-champion types later in life. Don't think the biographies I've read of him ever said whether he won or not, but I'd imagine not. Still, I've always been fascinated with chess and those that are really good at it.

But this post is about Romeo and Juliet, which I thought would fit well considering today's Valentines Day and all. In 1934, Prokofiev was commissioned by the famous Kirov Ballet to write a score for a new ballet.. The result? One of his most beloved works, and easily my favorite scoring of the Shakespeare tragedy. (Many other composers have set the story to music, including Berlioz, die-hard Romantic that he was, and Tchaikovsky, and come to think of it Radiohead, maybe too?)

violin_neck_250.jpgIn this excerpt, which is from the famous Balcony Scene, I want you to listen to the string writing. There's plenty of what I call the "Prokofiev trademark" here, which is that high-pitched, thin string moment where the violins take the melody into the extreme upper register. Very few composers have dared to write way up there because it's very hard for the violinists to stay in tune. Just like on a guitar, the higher up the neck you go, the smaller the space between notes. A violin neck is already pretty small, so you can imagine toward the end of the neck notes tend to be separated by millimeters. The chances of 12 violinists hitting the same spot at the same time aren't too hot, as you can imagine, so we wind up with a slightly out-of-tune quality. But just as basketball players now jump higher, and baseball players hit more homeruns* than ever, so violinists, over the last 100 years, have gotten much better, technically, and more accustomed to playing in the stratosphere. Prokofiev is one composer they can thank for that.

This classic footage features Margot Fonteyn and Rudolph Nureyev, the world's most popular pas de duex team at one time--worth watching even if you're not interested in the string writing!

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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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Name the Author Based on the Character
May 23, 2017
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