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Charlene McBride via Flickr // CC BY 2.0

Penny Pinching: A History of Coin Elongation Machines

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Charlene McBride via Flickr // CC BY 2.0

Visitors to the 1893 World’s Fair in Chicago—known at the time as the Columbian Exposition because it was the 400th anniversary of Columbus’s voyage—had an opportunity to see a lot of innovative new ideas for the first time. Wrigley’s debuted their chewing gum; guests got to ride a Ferris Wheel; if you were hungry, you could eat an early version of Cracker Jack. Constipated? Shredded Wheat premiered there, too.

But the one attraction that the throng of visitors couldn’t seem to get enough of was the penny press machine. For a nickel, a press operator would accept a coin from a guest, stick it between two industrial-strength rollers exerting several tons of pressure, and apply a hand crank. Out would come the coin—usually a penny—that had been squished and deformed so it now looked like an abstract flourish in a painting. Oval-shaped, it bore a stamp that had been embossed by a mold on one of the rollers: “Columbian Exposition 1893.”

Bev Sykes via Flickr // CC BY 2.0

Informally, they’re known as penny pressers, penny crushers, or squishers. To collectors, they’re coin elongation machines that produce elongated coins, flattened currency that uses your loose change to emboss a design depending on where the machine is found. In Roswell, New Mexico, machines will craft UFOs onto pennies; at the Audubon Aquarium in New Orleans, penguins and other animals appear; at Disneyland, you can get Mickey Mouse and countless other characters.

Elongated coins are part of what numismatists called exonumia, or oddball coins that don’t fit any standard definition of money. (Add wooden nickels to the list.) Although steam-powered press machines had been around as early as 1833 (and there are elongated coins believed to be from around 1818), it wasn’t until the 1893 Chicago exhibition where a modified jeweler's mill was on display—courtesy of an unknown but fairly clever jeweler—that they experienced a surge in popularity. Part of it was the theatrical experience—stick a seemingly indestructible coin in and watch it change shape—and part of it was having an inexpensive way of memorializing a visit to a popular attraction.

The coin presses began popping up around the country before experiencing a lull in 1916, and it wasn’t until 1932 that tourist spots started to see an uptick in their use. Another resurgence happened in 1976, the bicentennial, when collectors were eager for commemorative material from the celebration.

The rising interest continued in the 1980s, thanks in some measure to the Disney parks incorporating them into many of their high foot-traffic locations. Disney even has a full-time employee, Rob Johnson, who's in charge of maintaining their machines, often turning to companies like EuroLink for the engraving dies. Engravers like Jim Dundon often slip in their initials as a kind of artist's signature. Collectors who are serious about elongates prefer to find or use pennies made pre-1982, before the U.S. Mint switched to a predominantly zinc composition that made elongated pennies look prematurely dark and worn.

Liz Lawley via Flickr // CC BY-SA 2.0

It’s not known exactly how many of the elongation machines are installed around the U.S., but there are enough in use that some collectors use their location as markers for cross-country travel, sometimes even traveling to a specific destination to fill a hole in their collection. (Because the number of stamped coins is so vast, collectors sometimes stick to a specific genre, like space travel or politics.)

They take these self-styled “squishin’ missions” pretty seriously: One elongate enthusiast profiled in Colorado Life magazine admitted to nearly breaking down in tears when she saw a child jam the machine she had driven hundreds of miles to access. Another notable exonumia fan, Pete Morelewicz, ran a museum in Washington, D.C. for several years, complete with a hard-luck tale: once, a machine devoured the tip of his finger.

Once a penny has been spit out to a wafer-thin shape, can it be reused as currency? Probably not, but the U.S. Mint isn’t going to make a big deal of it. But if you use the squished coin to pass off a nickel for a quarter, that’s a very different matter. Providing you aren’t mutilating currency for counterfeiting purposes, they don’t have a problem with the machines. Just watch your fingers.

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iStock // Ekaterina Minaeva
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technology
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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Cs California, Wikimedia Commons // CC BY-SA 3.0
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science
How Experts Say We Should Stop a 'Zombie' Infection: Kill It With Fire
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Cs California, Wikimedia Commons // CC BY-SA 3.0

Scientists are known for being pretty cautious people. But sometimes, even the most careful of us need to burn some things to the ground. Immunologists have proposed a plan to burn large swaths of parkland in an attempt to wipe out disease, as The New York Times reports. They described the problem in the journal Microbiology and Molecular Biology Reviews.

Chronic wasting disease (CWD) is a gruesome infection that’s been destroying deer and elk herds across North America. Like bovine spongiform encephalopathy (BSE, better known as mad cow disease) and Creutzfeldt-Jakob disease, CWD is caused by damaged, contagious little proteins called prions. Although it's been half a century since CWD was first discovered, scientists are still scratching their heads about how it works, how it spreads, and if, like BSE, it could someday infect humans.

Paper co-author Mark Zabel, of the Prion Research Center at Colorado State University, says animals with CWD fade away slowly at first, losing weight and starting to act kind of spacey. But "they’re not hard to pick out at the end stage," he told The New York Times. "They have a vacant stare, they have a stumbling gait, their heads are drooping, their ears are down, you can see thick saliva dripping from their mouths. It’s like a true zombie disease."

CWD has already been spotted in 24 U.S. states. Some herds are already 50 percent infected, and that number is only growing.

Prion illnesses often travel from one infected individual to another, but CWD’s expansion was so rapid that scientists began to suspect it had more than one way of finding new animals to attack.

Sure enough, it did. As it turns out, the CWD prion doesn’t go down with its host-animal ship. Infected animals shed the prion in their urine, feces, and drool. Long after the sick deer has died, others can still contract CWD from the leaves they eat and the grass in which they stand.

As if that’s not bad enough, CWD has another trick up its sleeve: spontaneous generation. That is, it doesn’t take much damage to twist a healthy prion into a zombifying pathogen. The illness just pops up.

There are some treatments, including immersing infected tissue in an ozone bath. But that won't help when the problem is literally smeared across the landscape. "You cannot treat half of the continental United States with ozone," Zabel said.

And so, to combat this many-pronged assault on our wildlife, Zabel and his colleagues are getting aggressive. They recommend a controlled burn of infected areas of national parks in Colorado and Arkansas—a pilot study to determine if fire will be enough.

"If you eliminate the plants that have prions on the surface, that would be a huge step forward," he said. "I really don’t think it’s that crazy."

[h/t The New York Times]

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