Original image

Who gets the parking space?

Original image

Parking can be high drama in big cities like mine, so I guess I shouldn't be surprised to have witnessed two parking-related near-beatings in recent weeks, both misguided attempts to answer this enduring riddle: can you save a parking space for a friend by standing in it?

The first time I saw this drama play itself out, I was walking down the street in Culver City, talking on my cell phone, head in the clouds. I was quickly yanked out of my cellular reverie, however, when I heard shouting: "Go ahead, asshole, run me over!" There was a petite-but-feisty woman standing in a parking space, hands on hips, while an old man in a weathered Corolla inched toward her, ever further into the spot. "I'm saving this spot for my boyfriend, so get outta here!" she screamed, pointing behind her for added effect. The man continued to inch forward, bumper almost touching her knees, assuming that she would soon realize the folly of trying to challenge his right to the spot without a car of her own.

Soon enough, however, the boyfriend in question showed up. He was a big guy. He leaned down to the crack in the guy's driver-side window, and shouted "If you run my girlfriend over, I'll pull you out of that car and beat the s#!^ out of you!" At this point, I had passed the scene and didn't want to rubberneck too badly or risk getting pulled into the debate. (Plus, I was still on the phone, vainly trying to describe what was unfolding before my eyes to the person on the other end.) I kept walking. When I looked back again, the situation had somehow resolved itself: amazingly, the couple had left, and the unflappable old man had taken the spot.

I saw a similar fight just a week later, this one between two young women. The one behind the wheel had actually bumper-tapped her space-standing rival in the leg while attempting to force her out, prompting her to wave her cell phone in the air, shouting "This bitch just ran me over! I'm calling the cops!" Somehow, this worked itself out too, and minutes later all was quiet again in Santa Monica.

These things don't always work out so well in the end, however. Earlier this year in San Francisco, a man trying to hold a spot for a friend was shot dead by some guys in a van who disagreed with his parking etiquette. But so far as I can tell, there's no law on the books against space standing -- at least not in California. (There is in New York, however; you can get a $65 fine for holding a parking spot with anything other than a car.) In most places, though, it seems to be an open question -- heck, even Yahoo Answers couldn't settle the debate -- and the price of this legal ambiguity has been a uptick in "parking rage," and in some unfortunate cases, motorists' blood.

So what's the answer? Can you reserve a space by standing in it? Should a parker faced with an enraged space-stander back down?

Original image
iStock // Ekaterina Minaeva
Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
Original image
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!

Original image
Name the Author Based on the Character
May 23, 2017
Original image