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Big Money: Yap's Stone Currency

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Photo Credit: Flickr user annamatic3000

If you wanted to be a bank robber on Yap, you’d need a forklift and a crane, along with an 18-wheeler to make your getaway. That’s because for centuries, the main form of currency on this tiny Micronesian island was stones. Very large stones. Looking like Claes Oldenburg sculptures of oversized bagels, the stones – or rai, as they’re called – can stand as high as ten feet and weigh several tons each.

While these carved stones may not look like big bucks to an outsider, some have enough value to purchase a new house.

Of course, all currency, from beads to spices to paper bearing pictures of dead presidents, carries an arbitrary designation. It’s money because a culture says it is. And often, in the beginning, it’s money because it’s pleasing to the eye. Think of silver and gold. That’s the way it was with the stones on Yap.

According to local legend, five hundred years ago, Yapese fishermen got lost at sea and washed up on the island of Palau. There they saw some shimmering Limestone deposits and thought they looked beautiful. They broke off a piece of stone, carved it into the shape of a whale, brought it home and called it money. The Yapese word for whale is “rai,” and it soon became synonymous with all stone currency.

Photo Credit: Flickr user David Weekly

In time, the villages on Yap were launching regular expeditions to Palau to bring back more rai. For the right to quarry on their island, Palau residents were paid with various services, plus goods like beads and coconuts. As their mining process became more refined, the Yapese started carving the limestone into disks with holes, presumably because they were easier to carry. Poles were inserted through the centers and sailors hauled them to waiting boats. In the 19th century, the size of the rai grew markedly, as European traders equipped Yap natives with more modern tools.

The Value of a Giant Stone With a Hole In It

Though many of the large stones look similar, not all rai is of equal value. Its worth depends on several factors. The first has to do with its provenance. How many lives were lost in transporting the stone to Yap? In the old days, it was a treacherous journey by sea to obtain the stones. Beyond the mining and transportation across three hundred miles, there was also a lot of rivalry between village chiefs, resulting in fights to secure the rai.

The second factor has to do with who discovered a particular stone. Having a famous sailor’s name attached to it, or the dedication of a chief who sponsored the mining trip, can greatly increase the rai’s value. There’s also the matter of craftsmanship. Many of the newer rai stones are highly polished with smooth edges, a look that’s been achieved with imported modern metal tools. The older stones, less polished and rough-hewn, were finished with homegrown shell tools, which gives them a higher value.

Once transported to Yap, the stones were rarely moved. In fact, unlike most currency in the world, the rai were not hidden in banks, but publicly displayed, in ceremonial grounds and village centers. Even if their ownership changed hands from village to village, the stones remained in place, because everyone understood who owned them. Though there’s no direct parallel in our own currency, rai are a bit like bonds or certificates of deposit. They gain value over time, and are used only for major purchases.

For smaller, everyday transactions, there are other forms of money on Yap, including turmeric, pearl shells, banana fiber mat and mortars and pestles. And since the early 1990s, the American dollar and the Euro have found their way onto the island via a burgeoning new tourist trade.

Elsewhere on the Island...

And something much more unexpected from America may have also ended up on Yap. Remember New Coke? Back in the mid-‘80s, that was Coca-Cola’s misguided attempt to fix something that wasn’t broke. Public outcry resulted in Coke returning to their Classic formula. Meanwhile, New Coke, its sugary younger brother, lingered in the shadows until 2002, when it was discontinued. But according to various unconfirmed reports, New Coke, or Coke II as it's also known, has apparently found a small, but stable market on Yap.

No word on how much it costs per can, but chances are its somewhere between a pinch of turmeric and a ten-foot rai.

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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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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]

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