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Philibert Louis Debucourt, Detail from "Calendrier républicain" // Public Domain

211 Years Ago Today, the French Abandoned Their Decimal Calendar

Original image
Philibert Louis Debucourt, Detail from "Calendrier républicain" // Public Domain

In 1793, the French switched to French Revolutionary Time, creating a decimal system of time. A day had 10 hours, 100 minutes per hour, and 100 seconds per minute. The system was elegant, doing away with the complex math required for time calculations under a 24 hour/60 minute/60 second system. But it also brought huge headaches.

French Revolutionary Time came alongside the French Republican Calendar, a further attempt to rationalize time. Months were divided into three 10-day weeks, and there were 12 months. The leftover days needed to add up to 365 or 366 for the year were tacked onto the end of the year as holidays. This was a bit inelegant (days and years being hard to divide cleanly by 10), but at least it was less confusing than trying to sort out what time "noon" was (it was 5 o'clock).

French Revolutionary Time only lasted 17 months. By April 7, 1795 (in the Gregorian calendar), the time system became optional. Decimal clocks and decimal/standard hybrid clocks continued to be used for years, but for practicality, France returned to the same system of time as its neighbors.

The French Republican Calendar lasted far longer. It began in late 1793 and ran all the way through the end of 1805 (again in the Gregorian reckoning). On December 31, 1805, the French government chucked the system—in the year XIV, by Republican reckoning. This was due, of course, to the reign of Napoléon Bonaparte as Emperor. (Incidentally, his coronation occurred on 11 Frimaire, Year XIII of the French Republican Calendar—also known as 2 December, 1804. It took him more than a year to roll back the revolutionary calendar.) In any case, January 1, 1806 rolled around using the Gregorian calendar and the rest is history.

Of course, all this calendar-nerd stuff leads to the fact that you could still choose to use the French Republican Calendar. Indeed, Wikipedia will tell you the current day and year using the system, although you'll want to read up on the exquisite problems related to leap years (also helpfully detailed on Wikipedia).

For a bit more on decimal time (including several modern variants), check out our article Decimal Time: How the French Made a 10-Hour Day.

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iStock // Ekaterina Minaeva
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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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iStock
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Why Your iPhone Doesn't Always Show You the 'Decline Call' Button
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iStock

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]

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