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8 Octopus Facts (one for each arm)

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There's absolutely no telling how many moms and dads have reached a point during this holiday season when they've thought, "I can't do everything at once. I'm not an octopus, y'know!" Well, having eight arms might sound like fun, but there's more to being an octopus than spitting out ink and attending Detroit Red Wings games. Here are 8 facts about these fascinating aquatic creatures that you may not have known. Enjoy!

1. All varieties of octopus are venomous.

oct1.jpgFortunately, only a few species have enough venom to injure or kill a human being. One of these is the blue ringed octopus, which is responsible for at least two confirmed deaths. Octopi inject their venom using a tough beak-like mouth that sticks out of the side of their head. It's similar to a bird's beak and is made of the same tough material as a lobster's shell.

2. A female octopus, known as a hen, may lay 100 thousand eggs...

...over its one-to-two-week fertile period. The transparent eggs are protected by the mother in the octopus' lair for several weeks. In most species, the eggs hatch, and the larval octopi swim for the surface where they may remain for a month or more. The vast majority of them die during this period. Weather and turbulent water get many of them, while others are swallowed up along with plankton by larger sea creatures.

3. An octopus' "ink" serves three important purposes.

Most - but not all - octopus species come equipped with an "ink sac" that spews out a stream of dark liquid into the water when the creature is threatened. When frightened, an octopus often "swallows" water with its body and ejects it forcefully. This not only propels the animal away from the danger, but also forces out a trail of "ink." This ink, which may be red, brown, or black, is made of melanin, the same dark pigment that colors human skin and hair. The ink's effects are three-fold: First, the initial "jet" of ink visually distracts, confuses, and perhaps even frightens the predator. Secondly, it may interfere with the predator's sense of smell or sight. And third, once dispersed, the ink clouds the water to help give the octopus time to escape.

4. An octopus' suckers are arranged in two rows down each arm

Some species have more suckers than others. And while some species grow a standard number of suckers on each arm by the time they become adults, the number of suckers on the arms of other species may vary. In some cases, female octopi have more suckers than the men, but only because of what "makes the male the male." Read on.

5. One arm of a male octopus is, well, special.

The third right arm, to be exact. At the tip of this "hectocotylus" arm is the ligula, which serves as its reproductive organ. In some species, the arm is visibly different since it has fewer suckers than the other seven arms. When a male fertilizes a female's eggs, she doesn't necessarily lay them right away. She may hold them for days or weeks before she feels ready to do so.

6. An octopus sees the same thing upside down as right-side up.

oct2.jpgThe large and complex eyes of an octopus help it to perform the two functions most necessary for survival: finding food and avoiding trouble. While most of the rest of the creature's body is quite flexible in the water, the eyes are more solid. As a result, some species of octopus can squeeze through tight spaces only slightly larger than their eyes.

Oddly, an octopus' eyes have horizontal pupils (in direct contrast to felines, whose eyes have vertical pupils). What's even more unusual is that the octopus' eyes remain at the same orientation regardless of the creature's position. So if it turns on its side or even upside down, the gaze of the eyes remain fixed in relation to the horizon.

7. Octopi don't like the spotlight.

Octopi like to keep hidden away. They'll usually find a cave or a formation in the rocks that allows them to remain secluded, but smaller octopi may hide inside a clamshell. They can actually crawl inside and use their suckers to pull the shell closed. Once the creatures get larger, however, they find clamshells are more interesting because they tend to include a tasty clam. A hungry octopus may perform any of a number of steps to open a clamshell. It may drill into the shell using its beak, it may use digestive juices to soften up the shell to break inside, or it may use its suckers and arms to pull the shell apart.

8. An octopus may also eat its own.

A hungry adult octopus isn't shy about consuming young octopi. After all, the smaller creatures can't put up much of a fight.

What's more, a study published in the March 2008 edition of Marine and Freshwater Behaviour and Physiology describes a female octopus that attacked, suffocated, and spent two days eating a male who'd just mated with her 13 times over a 3.5-hour period. And you thought your significant other was needy...

Happy holidays, everyone!

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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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May 23, 2017
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