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Is your small change worth big bucks?

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I was thinking about yesterday's state quarters quiz (scroll down, it's not too far) and it got me wondering about our coins in general. Most people will "save" a buffalo nickel or a Mercury dime, since the fact that they're older designs makes it a reasonable bet that the coin is rare and perhaps worth a few times its face value. And while I'm not a coin collector per se, I do know a bit about the hobby, so I began to think about it from a casual person's point of view. And here's the question I came up with:

Are there any otherwise-normal-looking coins I might find in my pocket that are worth holding on to?

penny.jpgAnd the answer is: not likely. I took a brand new, hot-of-the-shelves coin value book (the 2008 U.S. Coin Digest) and panned through the types of coins currently in circulation and see if there's anything worth keeping an eye out for. You know, if there's, say, one particular Jefferson nickel that's worth a few bucks. And notwithstanding the one-in-a-billion errors that occur, here's what I found:

  • A Lincoln penny dated 1933 or earlier is worth 15 cents or more, but even the most pristine ones are worth no more than $100.
  • A Jefferson nickel dated 1938, 1942-45, or 1950 might be worth 25 to 75 cents in good shape.
  • A Roosevelt dime dated 1949S or 1950S is worth a buck in good shape.
  • A Washington quarter dated 1940 or earlier is worth $3 in good shape.

And you know what? That's it. No other coin type still in circulation is gonna be worth more than its face value. That includes Kennedy half-dollars, bicentennial quarters, and even steel pennies. Heck, even some older designs, like the Ben Franklin half dollars, have little collector's value once they're circulated.

So is it worth sorting through your change to see if you have any of these? That's up to you. I guess it's better than staring at the tile while you're waiting on the folks at White Castle to bag your order.

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iStock // Ekaterina Minaeva
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
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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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Name the Author Based on the Character
May 23, 2017
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