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5 Rediscovered Underground Temples

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In the past week, the discoveries of two very different and amazing underground temples were in the news. But they are not the only ones.

1. The Lupercale
Just last week, the first pictures of a recently-discovered underground grotto in Rome were released. The chamber is 26 feet high and 24 feet in diameter. The discovery was made about a year ago as workers were repairing the remains of Emperor Augustus' palace on the Palatine, a hill in Rome. Archaeologists believe it is the original Lupercale, the site where legend says the founders of Rome, Romulus and Remus, were nursed by a wolf after having been abandoned by their parents, the war god Mars and mortal priestess Rhea Silvia. The chamber is partly filled with debris, but the ceiling mosaic gives a glimpse of the majesty the temple had when it was in use 2,000 years ago.

2. The Temples of Damanhur
In 1978, Oberto Airaudi and a few friends began excavating the ground under the alpine hill in Italy on whch they lived. They dug for 16 years in secret, as they had no permit for the project. When authorities demanded to see the dig in 1992, they were astonished to find nine ornately-decorated chambers, with a total volume approaching 300,000 cubic feet! Although the Italian government seized the temples for a time and was going to destroy them, a retroactive permit was eventually issued. Airaudi (who prefers the name Falco) and his colleagues continue building the underground temples to this day, with plans for bigger and better underground chambers to come.

More on the Damanhur and other temples, after the jump.

Falco's organization, the Federation of Damanhur, runs tours of the Temples of Humankind complex, a two-day affair with a day of "preparation" and a day of viewing. The temples are not dedicated to any deity, but to humankind. They were built for meditation and spiritual renewal. See more photos of the temples of Humankind at the official website.

3. The Underground Temple at Hampi
The city of Hampi in Karnataka, India is a UNESCO World Heritage site as a grouping of Hindu monuments. One of these is the Underground Temple, believed to have been built in the 13th century and used until Muslim attacks left the city in ruins in the 16th century. This temple of Siva is underneath the water table, and the inner sanctum is usually flooded. However, tourists are welcome to go as far down the passageway as possible.

4. The Hypogeum at Hal Saflieni
The Hal Saflieni Hypogeum in Malta is a UNESCO World Heritage Site and the oldest underground temple we now know of. Its 500 square meters spread over three levels of halls, chambers, and passageways carved out between 3600 and 2500 BC. It was rediscovered in 1902 by a stonemason who was building houses over the temple. The Hypogeum is open to tourism, with a limit of 80 visitors a day, so reservations should be made far in advance. See more pictures at Malta Temples.

5. The Osireion
The Osireion is a false tomb connected to the Seti I temple at Abydos in Egypt. It is the mythical burial tomb of the ancient Egyptian god Osiris. Seti I reigned in the 13th century BC. The Osireion was built below the water table and was flooded much of the time before its 20th century excavation. It was discovered during an excavation in 1902, but not fully explored until 1926. Part of the Osireion is open to the surface now, but originally had limestone roofs below ground level. This photo by Ernesto Graf shows a section that is both exposed and flooded.

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iStock // Ekaterina Minaeva
Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
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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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Here's How to Change Your Name on Facebook
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Whether you want to change your legal name, adopt a new nickname, or simply reinvent your online persona, it's helpful to know the process of resetting your name on Facebook. The social media site isn't a fan of fake accounts, and as a result changing your name is a little more complicated than updating your profile picture or relationship status. Luckily, Daily Dot laid out the steps.

Start by going to the blue bar at the top of the page in desktop view and clicking the down arrow to the far right. From here, go to Settings. This should take you to the General Account Settings page. Find your name as it appears on your profile and click the Edit link to the right of it. Now, you can input your preferred first and last name, and if you’d like, your middle name.

The steps are similar in Facebook mobile. To find Settings, tap the More option in the bottom right corner. Go to Account Settings, then General, then hit your name to change it.

Whatever you type should adhere to Facebook's guidelines, which prohibit symbols, numbers, unusual capitalization, and honorifics like Mr., Ms., and Dr. Before landing on a name, make sure you’re ready to commit to it: Facebook won’t let you update it again for 60 days. If you aren’t happy with these restrictions, adding a secondary name or a name pronunciation might better suit your needs. You can do this by going to the Details About You heading under the About page of your profile.

[h/t Daily Dot]