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Beyond Black Friday: The 7 Black Days of the Week

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We all know Black Friday, the discount-fueled shopping frenzy that follows Thanksgiving. But there are “Black” days for Saturday, Sunday, Monday, Tuesday, Wednesday, and Thursday, too. You probably wouldn’t want to wake up early to wait in line for any of these.

1. Black Sunday

On Sunday, April 14, 1935, a massive dust storm swept through the Great Plains, the largest of the decade. The day came to be known as “Black Sunday” because the huge cloud of topsoil, over 300,000 tons of it, was coal-black.

Dirt from the storm reached all the way to Washington, D.C. Witnesses said “The impact [was] like a shovelful of fine sand flung against the face.” The so-called “black blizzard” even resulted in the press giving the area its famous nickname: The Dust Bowl.

Other Black Sundays: A large series of wildfires in Australia on Valentine’s Day, 1926 (and another in 1955); the disastrous opening day of Disneyland on July 17, 1955; and the death of Dale Earnhardt on February 18, 2001.

2. Black Monday

© JP Laffont/Sygma/Corbis

Monday, October 19, 1987, is known as Black Monday—the largest one-day percentage drop in stock market history. In a single day, the Dow Jones Industrial Average lost a quarter of its value. Overall, the market lost $1 trillion.

As for why it happened, it’s essentially the same explanation we have for our recent economic woes: A lot of complicated market-speak, finger-pointing, and no clear answers. CNBC has collected several theories here.

Other Black Mondays: A hail storm that killed 1,000 British troops during the Hundred Years’ War on Easter Monday in 1360; the closure of Youngstown Sheet and Tube in Youngstown, Ohio on September 19, 1977, which left thousands unemployed; and the assassination of San Francisco Mayor George Moscone and his advisor, Harvey Milk, on November 27, 1978.

3. Black Tuesday

While Black Monday may be the largest stock market crash in history, Black Tuesday is the most famous. On October 29, 1929, after two prior days of instability (referred to as Black Thursday and Black Monday, naturally), the stock market crashed completely, kicking off the Great Depression, the worst economic climate in American history.

In a matter of hours, the Dow Jones lost 23% of its value (just short of the nearly 25% lost in 1987) and a whole year’s worth of gains. Savings were wiped out overnight and $100 billion completely disappeared from the nation’s economy, which took a decade to recover.

Other Black Tuesdays: The November 22, 2011, South African protests against the “Protection of Information Bill”; the September 21, 1931, Estevan Riot in Saskatchewan, where three strikers were killed by RCMP officers; and the death of Fred Evans on November 12, 1912, the first worker killed during a strike in New Zealand’s history.

4. Black Wednesday

Bar image via Shutterstock

The day after Thanksgiving isn’t the only “Black” day in that week. Wednesday is becoming notorious too, albeit for a much sadder reason. Before college and high school students spend Thanksgiving weekend with their families, many spend the night out drinking with friends.

It’s come to be known as Black Wednesday among law enforcement agencies, reportedly because of students drinking until they black out. It’s been called the biggest day of the year for underage drinking.

Other Black Wednesdays: This year’s SOPA internet blackouts on Wednesday, January 18; and one of the worst days in air traffic history, September 15, 1954, when over 45,000 planes were delayed due to bad weather and overloaded air traffic control systems.

5. Black Thursday

There were many dark days during World War II, but none was worse for the USAAF (the predecessor to the U.S. Air Force) than Thursday, October 14, 1943, now known as Black Thursday.

Allied forces had become aware that the German army had a bottleneck in its production of military hardware. Ball bearings were in short supply and a large percentage were manufactured by factories located in the city of Schweinfurt. The Allies enacted a plan to bomb the factories, something they’d done previously just a few months before.

Unfortunately, due to a combination of bad weather and strong German anti-air support, the USAAF lost sixty planes and 600 crewmembers that day. It wound up being their worst loss in the entire war.

Other Black Thursdays: The failure of Jay Cooke and Company on September 18, 1873, which was one of the initiating events of the Panic of 1873; and the Black World Wide Web protest of February 8, 1996, where major websites turned their backgrounds black to protest the Communications Decency Act.

6. Black Friday

© Bob Campbell/San Francisco Chronicle/Corbis

The House Subcommittee on Un-American Activities, Congressmen tasked with uncovering communist sympathizers both inside and outside of the U.S. government, was once one of the most feared groups in America. Even the mere accusation of communist tendencies led to the immediate end of many careers in Hollywood.

By 1960, however, the group’s power had faded and the public had begun to find their tactics distasteful. This set the stage for the May 13, 1960, protest in San Francisco that became known as “Black Friday.” Students protesting the Subcommittee’s hearings were met with fire hoses and clubs, and 64 were arrested. Some also credit the protest with kicking off the idea of student activism, which would become a major fixture of the rest of the decade.

Other Black Fridays: The arrest of seven Anglican bishops for “seditious libel” by King James II on June 8, 1688; a hurricane near Eyemouth, Scotland on October 14, 1881, which killed nearly 200 fishermen; and the assassination of John F. Kennedy on November 22, 1963. And of course today the term is used for the day after Thanksgiving, which was coined in Philadelphia in the 1960s.

7. Black Saturday

At the height of the Cold War, everyone looked like an enemy to the United States, and none was more threatening than the one just off-shore. For thirteen days in October of 1962, America and Russia (by way of its ally, Cuba) both had their fingers on the triggers of their nuclear arsenals.

Finally, on Black Saturday, October 27, things came to a head. Soviet forces in Cuba shot down a U-2 spy plane, leading both armies to begin preparing for war. Tensions on both sides flared, but hours later, with things still looking very grim, President Kennedy, Fidel Castro, and Premier Nikita Khrushchev finally reached a diplomatic agreement to stop further escalations.

Other Black Saturdays: A very bad thunderstorm that coincided with the passing of the Articles of Perth in Scotland on August 4, 1621, which some at the time felt was very ominous; and the day of the worst fires in Yellowstone National Park history on August 20, 1988.

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iStock // Ekaterina Minaeva
Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
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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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Why Your iPhone Doesn't Always Show You the 'Decline Call' Button
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When you get an incoming call to your iPhone, the options that light up your screen aren't always the same. Sometimes you have the option to decline a call, and sometimes you only see a slider that allows you to answer, without an option to send the caller straight to voicemail. Why the difference?

A while back, Business Insider tracked down the answer to this conundrum of modern communication, and the answer turns out to be fairly simple.

If you get a call while your phone is locked, you’ll see the "slide to answer" button. In order to decline the call, you have to double-tap the power button on the top of the phone.

If your phone is unlocked, however, the screen that appears during an incoming call is different. You’ll see the two buttons, "accept" or "decline."

Either way, you get the options to set a reminder to call that person back or to immediately send them a text message. ("Dad, stop calling me at work, it’s 9 a.m.!")

[h/t Business Insider]