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How to Use Toilet Paper

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Certain aspects of human life are simultaneously private and universal -- everyone experiences the same stuff privately and almost no one talks about it. Pretty much everything that happens in the bathroom falls into this category, which is why I was amazed to discover that serious thought has gone into the challenges presented by toilet paper. Here are a few examples.

The Toilet Paper Algorithm

Design guru Don Norman decided to confront a common toilet paper crisis: the problem of the roll running out just when you need it most. When remodeling his home, Norman installed a dual-roll toilet paper dispenser, under the theory that there'd always be a second roll available for just such emergencies. But he quickly found that, for some reason, both rolls seemed to run out at the same time!

Norman applied some logical thinking to his problem, resulting in the article Toilet Paper Algorithms: I didn't know you had to be a computer scientist to use toilet paper. The gist of it is that Norman and his wife were subconsciously selecting whatever roll was larger at any given time, leading them both to become roughly the same size, thus running out at the same time. (Read the article for more details on the various available toilet paper algorithms...it's neat.)

For the record, Norman determined that the optimal strategy for using toilet paper in a dual-roll holder is to always use the smaller roll. This will tend to drive one roll to become empty, but will leave a full roll available.

Norman isn't alone in his analysis of toilet paper roll consumption -- Donald E. Knuth published a mathematics paper entitled The Toilet Paper Problem in The American Mathematical Monthly in 1984, including equations for analysis of toilet paper usage.

The Fold Versus Crumple Debate

I'll try to put this as delicately as I can. Apparently there's a significant debate about whether it's better to fold several sheets of paper, or crumple them together in a bunch. One major argument in favor of the "fold" method is that depending on the quality of your paper and your folding technique, you can refold (and thus reuse) a single set of sheets. The counter-argument is that this is super-gross. I have my own opinions on this issue, but let's just say I've tried multiple methodologies over the years and feel that I've perfected my technique.

So what's the distribution of crumplers versus folders in the wild? An online toilet paper usage survey has received almost 5,000 responses. At the moment, the folders are slightly in the lead (52%), but tend to be a little older than crumplers. Also, far more crumplers are male than female (70% of crumplers in the survey are male). You can take the survey or just hit the 'View' button to see the results without contributing your own.

Toilet Paper Requisition Denied

Here's some fun WWII trivia. Lieutenant Commander J. W. Coe of the submarine USS Skipjack requested 150 rolls of toilet paper from the supply officer at Mare Island Naval Base in July of 1941. The request was denied in November of 1941 with a notation saying, "Cancelled -- cannot identify." By June 1942 the situation onboard USS Skipjack was dire, and Coe sent another request, reading in part:

During the 11-3/4 months elapsing from the time of ordering the toilet paper and the present date, USS SKIPJACK personnel, despite their best efforts to await delivery of the subject material, have been unable to wait on numerous occasions, and the situation is now quite acute, particularly during depth-charge attacks by the "back stabbers."

...

SKIPJACK personnel during this period have become accustomed to the use of "crests," i.e., the vast amount of incoming non-essential paper work, and in so doing feel that the wish of the Bureau of Ships for reduction of paper work is being complied with, thus killing two birds with one stone.

Read the rest at the wonderful Snopes page detailing the event.

Got any toilet paper trivia, or an opinion on fold-versus-crumple? Share it with us in the comments!

(Toilet paper photo courtesy of Brandon Blinkenberg and Wikimedia Commons.)

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iStock // Ekaterina Minaeva
technology
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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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Animals
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Scientists Think They Know How Whales Got So Big
May 24, 2017
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It can be difficult to understand how enormous the blue whale—the largest animal to ever exist—really is. The mammal can measure up to 105 feet long, have a tongue that can weigh as much as an elephant, and have a massive, golf cart–sized heart powering a 200-ton frame. But while the blue whale might currently be the Andre the Giant of the sea, it wasn’t always so imposing.

For the majority of the 30 million years that baleen whales (the blue whale is one) have occupied the Earth, the mammals usually topped off at roughly 30 feet in length. It wasn’t until about 3 million years ago that the clade of whales experienced an evolutionary growth spurt, tripling in size. And scientists haven’t had any concrete idea why, Wired reports.

A study published in the journal Proceedings of the Royal Society B might help change that. Researchers examined fossil records and studied phylogenetic models (evolutionary relationships) among baleen whales, and found some evidence that climate change may have been the catalyst for turning the large animals into behemoths.

As the ice ages wore on and oceans were receiving nutrient-rich runoff, the whales encountered an increasing number of krill—the small, shrimp-like creatures that provided a food source—resulting from upwelling waters. The more they ate, the more they grew, and their bodies adapted over time. Their mouths grew larger and their fat stores increased, helping them to fuel longer migrations to additional food-enriched areas. Today blue whales eat up to four tons of krill every day.

If climate change set the ancestors of the blue whale on the path to its enormous size today, the study invites the question of what it might do to them in the future. Changes in ocean currents or temperature could alter the amount of available nutrients to whales, cutting off their food supply. With demand for whale oil in the 1900s having already dented their numbers, scientists are hoping that further shifts in their oceanic ecosystem won’t relegate them to history.

[h/t Wired]

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