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Music History #13: "Midnight Rambler"

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“Midnight Rambler”
Written by Mick Jagger & Keith Richards (1969)
Performed by The Rolling Stones

The Music

Neither Mick Jagger or Keith Richards ever admitted directly that this song was about the notorious serial killer known as the Boston Strangler. But at four and a half minutes into the song, Jagger sings, “Well, did you hear about the Boston . . .” and it brings the rest of the lyric into focus. With references to the title character “wrapped up in a black cat cloak,” “jumping the garden wall,” and “sticking a knife right down your throat,” it’s clear enough the song is about some kind of killer.

“Midnight Rambler” was never a single, but has long been a featured part of the band’s live set. Elsewhere in pop culture, the Boston Strangler was also the subject of a 1968 movie with Tony Curtis, and the case has been invoked in several TV shows, including American Gothic and Rizzoli & Isles.

The History

Photo Courtesy Rare Newspapers

Between June 1962 and January 1964, 13 women were murdered in and around the Boston area. Most of them were sexually assaulted, then strangled in their apartments. The killer’s grotesque flourish was to tie a bow around the victims’ necks, using their nylon stockings. What confounded the police was there was never any sign of forced entry in the homes. The women either knew the murderer, or voluntarily let him in the door. And even with the increasing coverage of the serial killer in the papers and on TV, the attacks continued.

The first seven victims suggested a pattern. They were all single white women between the ages of 55 and 85 who lived alone. The police surmised that they were looking for a white male who hated his mother, and was acting out his rage repeatedly. But the next murder broke the pattern. The victim was a 20-year-old black woman who shared an apartment with someone. The murders continued, with the pattern varying slightly each time. The only constant was the nylon stocking bow. By early 1964, several police forces in Massachusetts, along with FBI agents and even a psychic, were coordinating efforts to try to stop the killer.

Then in October 1964, they caught a break. A stranger posing as a detective entered a woman’s home, tied her to the bed, sexually assaulted her, then fled, saying, “I’m sorry.” The woman’s description of the assailant eventually led the police to arrest a man named Albert DeSalvo. He confessed to all the killings.

Case closed. Or was it?

The Wrong Man

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Albert DeSalvo was a convicted sex offender and a patient in a Boston mental institution. In early 1965, he told a fellow inmate that he had committed the murders. The inmate then relayed this information to an attorney, F. Lee Bailey. DeSalvo was put on trial.

What convinced the police they’d caught the real Strangler was the accuracy of DeSalvo’s descriptions of the various crime scenes. He remembered small, telling details—like the brand of a pack of cigarettes knocked to the floor beside a bureau, or the apartment number etched in gold on a glass storm door. His attorney Bailey later said, “He would close his eyes, then as if he were watching a videotape replay, he would describe what had happened.”

It was a compelling reason to believe he was guilty. But there was a problem: There was no physical evidence, such as fingerprints, at any of the crime scenes linking DeSalvo to the murders. Nor were there any eyewitnesses.

Another inconsistency: DeSalvo claimed that he drove his car to all the murder scenes. But some of the locations would have posed impossible parking situations. Where did he park? Why couldn’t anyone find the parking receipts?

Because he was a mental patient, DeSalvo’s confession couldn’t be used against him. Consequently, he stood trial only for his earlier crimes of robbery and sexual assault. During his defense, Bailey wove in the confession to the stranglings in order to convince the jury that DeSalvo was “not guilty by reason of insanity.” The judge refused to accept the insanity verdict, and in 1967, DeSalvo was sentenced to life in prison.

Further Doubts

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The same year, DeSalvo escaped from jail with two fellow inmates (weird trivia: one of them was named George Harrison). He gave himself up the next day, and was thrown into maximum security. Six years later, DeSalvo was found stabbed to death in the prison infirmary. His killer was never identified.

Was DeSalvo the Boston Strangler? Doubts still remain. There’s the lack of physical evidence, and the pattern variations in the crimes. FBI profiler Robert Ressler said, “You’re putting together so many different patterns that it’s inconceivable behaviorally that all these could fit one individual.” It’s also believed that DeSalvo’s visual recall of the crimes could’ve easily been gleaned from newspaper reports and photos that he memorized. Susan Kelly, author of The Boston Stranglers, a book that proposes there were several killers, said, “It’s very interesting to me that the details that Albert got wrong in his confession were identical to the details that the newspapers got wrong.”

In 2000, the case was reopened. The body of the Strangler’s final victim, Mary Sullivan, was exhumed, along with DeSalvo’s. More inconsistencies were found. DeSalvo had claimed that he had sexual intercourse with the victim then strangled her with his bare hands. Forensics proved that neither was true. The investigation continues to this day; the true identity of the Boston Strangler may never be known.

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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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