CLOSE
Original image
IStock

13 Reasons People Think the Number 13 is Unlucky

Original image
IStock

Happy Friday the 13th! Why is the number 13 considered unlucky, anyway? Here are 13 possible reasons.

1. THERE WERE 13 PEOPLE AT THE LAST SUPPER.

And tradition has held that the 13th to take their seat was either Judas or Jesus himself.

2. MANY BELIEVE EITHER THE LAST SUPPER OR THE CRUCIFIXION OCCURRED ON THE 13TH.

One of the great controversies surrounding the Last Supper is whether or not it was a Passover meal. John seems to suggest that the meal was eaten the day before Passover, which has led some scholars to date the Last Supper to the 13th of Nisan (a month on the Jewish calendar), while others say that the crucifixion itself was on the 13th of Nisan.

3. BIBLICAL REFERENCES TO THE NUMBER 13 AREN'T ALL THAT POSITIVE.

According to historian Vincent Foster Hopper, one of the people who really pushed 13 as being unlucky was 16th century numerologist Petrus Bungus. Among his reasons? Hopper says that Bungus "records that the Jews murmured 13 times against God in the exodus from Egypt, that the thirteenth psalm concerns wickedness and corruption, that the circumcision of Israel occurred in the thirteenth year."

4. TRADITIONALLY, THERE WERE 13 STEPS TO THE GALLOWS.

According to popular lore, there are 13 steps leading up to the gallows. Gallows actually varied wildly, but even then, the number was often brought up to 13. A park ranger at Fort Smith Historic Site once said, "[There were] 13 steps on the gallows—12 up, and one down."

5. THE MASS ARREST AND EXECUTION OF THE KNIGHTS TEMPLAR BEGAN ON FRIDAY THE 13TH.

The Knights Templar, who were widely believed to be protecting the Holy Grail (the cup Jesus drank from at the Last Supper) as well as other holy objects, also acted as a bank of sorts to European kings. But after French King Philip IV lost a war with England and became heavily indebted to the Knights, he conspired with Pope Clement V to have all members of the Knights Templar arrested, charged with Satanism and other crimes, and massacred. The roundup of the Knights Templar began in earnest on Friday, October 13, 1307.

6. WOMEN MENSTRUATE ROUGHLY 13 TIMES A YEAR.

Some suggest that the association with 13 being unlucky is due to women generally having around 13 menstrual cycles a year (based on a cycle length of 28 days).

7. A WITCHES' COVEN HAS 13 MEMBERS.

Although a coven is now considered to be any group of witches (or vampires, in some tellings), it was once believed that a coven was made up of exactly 13 members.

8. 13 LETTERS IN A NAME MEANS THE PERSON IS CURSED.

There’s an old superstition that says if you have 13 letters in your name, you’re bound to be cursed. Silly, yes, but slightly more convincing when you consider that a number of notorious murderers' names (Charles Manson, Jack the Ripper, Jeffrey Dahmer, Theodore Bundy, and Albert De Salvo) all contain 13 letters. And, in case you were wondering: Adolf Hitler's baptismal name was Adolfus Hitler [PDF].

9. SUPERSTITION HAS MADE FRIDAY THE 13TH TOUGH FOR BUSINESSES.

Friday the 13th is an expensive day for businesses. One analyst claims that around a billion dollars a year are lost as people choose not to do business of any kind on Friday the 13th.

10. 12 IS A PERFECT NUMBER, SO 13 MUST BE UNLUCKY.

In some schools of numerology, the number 12 is considered to be the representation of perfection and completion. It stands to reason, then, that trying to improve upon perfection by adding a digit is a very bad idea indeed—your greed will be rewarded with bad luck.

11. ZOROASTRIAN TRADITION PREDICTS CHAOS IN THE 13TH MILLENNIUM.

The ancient Persians divided history into four chunks of 3000 years. And although the exact timeframes can vary, some scholars feel that at the beginning of the 13,000th year there will be chaos as evil mounts a great battle against good (although good will eventually triumph).

12. SPORTS GREATS WITH JERSEY NUMBER 13 SOMETIMES COME UP SHORT.

Dan Marino is a constant fixture at or near the top of any "best quarterbacks to never win a Super Bowl" list. Perhaps his failure to grab the biggest prize in football comes down to his jersey number—13. And he's not the only example: Basketball star Steve Nash was a two-time NBA MVP and is considered one of the all-time great point guards, but he and his #13 jersey never won a championship.

13. SUPER BOWL XIII WAS A HUGE FINANCIAL SETBACK FOR SPORTS BOOKIES.

And keeping with sports, 1979's Super Bowl XIII was a particularly bad one for bookies. Called "Black Sunday," it pitted the Dallas Cowboys, the defending champions, against the Pittsburgh Steelers. But as money kept pouring in from Texas and Pennsylvania, the spread kept changing until settling precisely at the game’s actual spread. The losses were legendary.

To counter all of this undue hatred of the poor number 13, here's one reason to love it: a baker’s dozen. Mmm, extra doughnut.

A version of this story ran in 2010.

Original image
iStock // Ekaterina Minaeva
technology
arrow
Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
Original image
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!

Original image
quiz
arrow
Name the Author Based on the Character
May 23, 2017
Original image
SECTIONS
BIG QUESTIONS
BIG QUESTIONS
WEATHER WATCH
BE THE CHANGE
JOB SECRETS
QUIZZES
WORLD WAR 1
SMART SHOPPING
STONES, BONES, & WRECKS
#TBT
THE PRESIDENTS
WORDS
RETROBITUARIES