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Famous assassins: where are they now?

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Name: Mark David Chapman
Crime: Video didn't kill this radio star; Mark David Chapman did. On December 8, 1980 he fatally shot John Lennon in front of the singer's New York city apartment building (the Dakota, also famously the location for Roman Polanski's creepfest Rosemary's Baby)
Where are they now? Attica. Yesterday its parole board denied him his freedom a fourth time, noting the "bizarre nature" of his crime. (Also, Chapman is regularly flooded with hate mail in prison, and it's thought that releasing him would essentially constitute a death sentence.)
Mark's lit picks: After the shooting, he calmly seated himself on the sidewalk and began reading The Catcher in the Rye. (He was arrested "without incident.") Echoing Catcher's protagonist, Holden Caulfield, he famously accused Lennon of being a "phoney."

john-hinckley.jpgName: John Hinckley, Jr.
Crime: The near-assassination of then-president Ronald Reagan on March 30, 1981, outside a Washington hotel.
John's favorite movie: 1976's Taxi Driver, about a man plotting the assassination of a political candidate. But Hinckley claims he wasn't just imitating the film's psycho-killer protagonist, Travis Bickle (Robert DeNiro), instead he had developed a serious obsession with co-star Jodie Foster. After creepily stalking her on and off for years, he decided the best way to impress her would be to kill a sitting president, thus making himself an historical figure, and -- to his mind, at least -- her equal.
Where are they now? Hinckley was judged not guilty by reason of insanity, sparking nationwide anger and prompting several states to rewrite the rules of their insanity pleas. He's been chillin' like a villain at St. Elizabeth's Mental Hospital in D.C. for the last 25 years, and recently has been judged safe enough to be allowed supervised trips outside the hospital to visit his elderly parents. He was disciplined after one such trip in 2000, however, after smuggling Foster-related materials back into the hostpial.
Fun facts: Hinckley was reportedly inspired by celebrity-killer Mark David Chapman, to whom he bears an uncanny resemblance.

Sirhan_Sirhan.gifName: Sirhan Sirhan
Crime: The murder of Robert F. Kennedy in the kitchen of Los Angeles' Ambassador Hotel on June 5, 1968.
What made him do it? God knows. Though the Palestinian-born Sirhan cited Kennedy's support for Israel's 1967 Six-Day War, he obsessively rants that "Kennedy must die" in diary entries which predate that event. As is seemingly true of most high-profile crimes these days, some believe the CIA was involved, claiming that Sirhan was brainwashed by their top-secret MKULTRA mind-control program, and under hypnosis at the time of the shooting. (Sirhan claims that he has complete memory blackout of the event, and even hypnosis therapy has not been able to elicit any details of the killing from him.)
Where are they now: the Corcoran State Prison in California, along with Charles Manson and serial machete-killer Juan Vellejo Corona.

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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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May 23, 2017
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