How Not To: Build an Inland Sea

When Life Gives You Massive River Flooding, Make Lemonade
In a fit of early 1900s nature-subduing enthusiasm, the good people of California decided to turn Imperial Valley (a desert) into a vast agricultural paradise (not a desert). To do so, they started cutting irrigation channels from the Colorado River. When those filled up with silt, they cut a little deeper, digging out a large gap in the River's bank to increase flow. Then, in 1905, the floods came, washing out the engineered canal and pouring thousands of gallons of water directly from the River into a previously dry below-sea-level basin. It took two years to get the flooding under control, by which point the basin had become a lake—the Salton Sea. In 1907 the first sport fish were imported and a tourist attraction was born.

Put Your Trust in Runoff

With the broken canals now repaired, the Salton Sea had no inlet or outlet. Instead, all it's water came from farm irrigation runoff. At first, nobody saw this as a problem. Then the Sea's salinity (and pollution levels) started to increase. Turns out, farmers were pulling water from the Sea, putting it on their crops, and letting it flow back in. Each time, the water picked up a little more salt and a few more pesticide chemicals. Eventually, this led to outbreaks of algae, massive fish die-offs, and a salinity level greater than the Pacific Ocean.

Assume You Won't Have To Deal With More Flooding In the Future

By the 1960s, regardless of its increasingly salty nature, the Salton Sea had become one of California's busiest tourist attractions and it's most popular state park. Investors built swanky resorts, but, unfortunately, nobody thought to build flood control systems. Then came 1976, when a tropical storm hit the area, marking the beginning of seven years of extra-heavy rains. Most of the new developments ended up underwater or bankrupt as investors bailed. Worse, increased runoff meant that even more chemicals and salt poured into the Sea. By the 1980s, there was little left of the once-thriving fishing and boating industries. Today, the Sea is home to several half-flooded trailer-park communities and one thriving bird sanctuary. Still ever saltier, it's expected to lose most of its fish population in the next few years.

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iStock // Ekaterina Minaeva
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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