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How Did You Know? [Day 5]

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If you've made it this far, I commend you! One more puzzle to solve and you're home free. First one to send in the correct answer to the challenge below, along with the correct answers found all along the path this week, AND, the logic behind "˜em (which is to say: HOW DID YOU KNOW?), gets a pick of any t-shirt or book from our store.

As comments have been turned off for the length of the hunt, please click on the following link and send your answers and logic to us at: TriviaHunt@Gmail.com.

If you missed Monday, Tuesday, Wednesday and Thursday's challenges, there might still be time to solve them all. No one knows how long it'll take for one of you trivia junkies to nail down the whole megillah so make haste, make haste. And now, on the next page, I present the final puzzle, drawing on all the answers you dug up along the trail.

F I L L  I N  T H E  B L A N K S:

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Day 1: Each of Monday's answers has something in common, namely, a band. What is the name of the band?

Day 2: Only one of Tuesday's answers spells a new word when turned backwards. What is the new word?

Day 3: On Wednesday you were asked to single out the one video or headline that stood apart from the others. All the others had two words in common. What were those two words?

Day 4: Every album on Thursday had something in common. They all what?

Day 5: Once you plug in the above Day 1-4 answers, you'll know what album title I'm looking for here.

Remember, in addition to solving the puzzle, I need the How Did You Know? component to name a winner. For instance, it's not enough to know the Day 1 answer above. I also want to know how you arrived at that answer. (e.g. What DO all five of Monday's songs have in common?)

Ready to submit? E-mail us by clicking the following link: TriviaHunt@Gmail.com. Along with your submission, we'd love to hear what you thought of this little week-long trivia feature. Was it too hard? Too easy? Do you want more of 'em? What was your favorite challenge? etc. The feedback would be most appreciated.

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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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