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Slow, but Scary, Killer Snails

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Wikimedia Commons

The killers in some classic slasher movies are notoriously slow. Jason Voorhees, Michael Myers, and Leatherface all shamble along at a pace that makes little old ladies look like Usain Bolt. It’s got to be frustrating for someone with murder on their mind to get outrun by their victims. But real-world slow-and-scaries, the predatory cone snails of the genus Conus, have evolved a frightening way to make up for their speed deficit: venomous, harpoon-like teeth that can stab prey and drag them to the snail.

The snails bury themselves in the sand and lie in wait or sneak up on their prey, using a specialized chemical-sensory organ to detect a meal. Once a victim is in range, the snail strikes. It points its long, flexible proboscis at its victim and launches a modified radular tooth—hollow, barbed and made of chitin—from it. The tooth is loaded with a cocktail of neurotoxins that reduce pain to pacify the prey and quickly paralyze it by blocking neurotransmitter receptors. The tooth is still attached to the radula structure, so once the prey is subdued, the snail draws both the tooth and its dinner right into its mouth. After the meal has been processed, the snail pukes up any leftover indigestible bits along with the used tooth, and readies another one to fire. You can see the a snail do the jab-and-grab and then swallow a fish whole in this National Geographic video.

The snail’s venom gland and the toxins it makes have fascinated scientists for more than a century. A researcher from Canada’s University of Victoria recently discovered that the venom glands of the species C. lividus come from a bit of “epithelial [tissue] remodeling” and are formed when a part of the esophagus pinches off as the snail transitions into adulthood. The researcher suggests that this tissue tweaking process allowed the snail to develop its weaponry and become carnivorous in a relatively short evolutionary timeframe.

Meanwhile, the speed and precision of the snails’ venom have led other researchers to look into it for medical use as a painkiller with few or no side effects. One painkiller derived from the snails’ arsenal has already been approved by the FDA. “Prialt” contains ziconotide, a synthetic equivalent of one of the snails’ many toxins, and is approved for use in treating chronic pain in patients with cancer and AIDS. Dozens of other cone snail toxins are still being investigated for use in pain relief and treating epilepsy, cardiovascular disease, Alzheimer’s, Parkinson’s, and other diseases and disorders.

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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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