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7 Tips for Traveling to Cuba

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If your interest in visiting Cuba has been piqued since President Obama's 2014 announcement of plans to improve relations between the United States and Cuba, you’re in luck: One of the areas in which swift changes have been made is travel. Several U.S. airlines launched direct flights to a handful of Cuban cities in August 2016, and tickets remain affordable and available. Here’s what you need to know to plan your own trip to Cuba.


For the first time in the history of the internet, U.S. travelers can book their flights to Cuba online. While flights still can’t be purchased through Expedia, all of the commercial airlines that offer flights—including American, Delta, JetBlue, and Spirit—allow online booking, and a few aggregator sites do as well, including CheapOair (which offers flights from JFK Airport in New York to Holguín).

But just because you can buy your flights from your laptop while lying in bed doesn’t mean the process is simple. Once you book your ticket, you’ll still need to purchase a travel visa (which you can’t yet do online) and you’ll need to be prepared to prove that you fall into one of the 12 categories of approved travelers published by the U.S. Department of Treasury. While word on the street is that authorities aren’t actually checking records to determine whether educational and “people-to-people” trips conform to DoT rules, you’ll want to be sure to stay within the letter of the law.

If you have questions, ask your airline, but remember: Commercial flights are still relatively new, and many airline agents aren’t yet familiar with specific regulations. When possible, get the name and title of the person with whom you speak for accountability’s sake.


Many airlines and airports offering direct flights to Cuba locate their Cuba flight check-in operations outside the usual “Departures” area. Give yourself the full three pre-departure hours recommended for international flights, and contact the airline prior to your flight date to ask where you’ll need to check in. Also, bear in mind that curbside check-in and similar amenities often are not available for Cuba-bound flights, even if you hold a special reward or member status with an airline.


While several major U.S.-issued debit and credit card companies rushed to announce they were arranging for their cards to be usable in Cuba, they've been slow to make good on their word. In December 2015, one small Florida bank was reported to be the first U.S. bank to forge a relationship with Cuba's central bank, and in June 2016 they debuted the first U.S. credit card to work there. But don't get your hopes up: Very few Cuban vendors have point-of-sale machines that work with U.S. plastic.

With none of the large U.S. banks operating in Cuba, you also can't withdraw cash from Cuban ATMs. Which means you need to bring your funds with you. The catch here is that you will always lose an automatic 10 percent when you exchange U.S. dollars into CUCs (Cuban Convertible Pesos) at a CADECA (the official currency exchange office). Finally, Cuba still has a dual-currency system. There are CUCs, which tourists tend to use, and CUPs (Cuban Pesos), which Cubans tend to use. When being charged for goods or services, be sure to ask what currency is being used. While there has been talk about moving to a one-currency system since 2013, no timeline has been announced and both currencies remain in effect as of this writing.


In many ways, Cuba—or Havana, at least—is more digitally connected than it has ever been. Wi-Fi service is increasingly ubiquitous in the capital’s parks and public spaces, and prices for Wi-Fi access dropped significantly in December 2016. And with AT&T announcing roaming capabilities in October 2016, it’s possible to stay connected throughout your visit to Cuba. However, service can be pretty pricey, at $3 per minute for voice and $2.05 per MB of data. It may be easier (on your wallet and mind) to just disconnect completely.


I’m a traveler who’s typically happy to forgo trip planning micro-management in favor of serendipity, but when it comes to accommodations in Cuba, this is not a good plan. Upon landing and proceeding to Immigration, you’ll be required to provide the address of your lodgings while in Cuba. Beyond potentially causing problems with entry into the country, you will also be hard-pressed to find accommodations if you don’t know Cuba well and you wait until you land to look for a place to stay.

Airbnb now lists more than 300 options all over the island and is likely the most affordable, accessible, and simple way for Americans to book a place to stay before they touch down.


Don’t worry about rum and cigar limits! In October 2015, the Obama administration announced that Americans returning from trips to Cuba can pack their bags with as much alcohol and cigars as they can carry (subject to the standard duties and limitations, of course). Be sure your wares are legit, though; plenty of hustlers, including employees at cigar factories, are keen to sell boxes at cut rates, but these boxes aren’t likely to pass muster if inspected. Waited 'til the last minute to do your shopping? You can buy cigars at Duty Free shops in the Havana airport.


It's important to remember that these policies are still in flux, so stay apprised of changes by regularly checking in with the Department of Treasury’s Office of Foreign Assets Control.

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iStock // Ekaterina Minaeva
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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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]