Writer Randall Munroe answers bizarre questions with math, like what would happen if a baseball pitcher threw a ball at 90 percent the speed of light? James Duncan Davidson/Courtesy of TED hide caption

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U.S. taxpayers have poured $30 billion into funding electronic records systems in hospitals and doctors' offices since 2009. But most of those systems still can't talk to each other, which makes transfer of medical information tough. iStockphoto hide caption

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A man walks by with a basket of bread during the official presentation ceremony of three new robots that were installed Tuesday in Kinshasa, Democratic Republic of Congo, to help tackle the city's traffic. Federico Scoppa/AFP/Getty Images hide caption

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A sign at Etsy's Brooklyn office in 2007 encapsulated the company's ambitious goal: Take down big-box retailers by selling handmade goods. Now Etsy, which in 2012 began allowing some mass-produced goods on its e-commerce site, is filing for an IPO, and trying to maintain its values as it expands. Amit Gupta/Flickr hide caption

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MIT is one of several schools that offer classes through edX, which provides free online courses in partnership with some of the country's top universities. Joe Raedle/Getty Images hide caption

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More than 600 Porto city buses and taxis have been fitted with routers to provide free Wi-Fi service. It's being touted as the biggest Wi-Fi-in-motion network in the world. Sérgio Rodrigues/Veniam hide caption

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The sun sets as a visitor uses his mobile phone Monday during the opening day of the 2015 Mobile World Congress in Barcelona. Wall Street Journal reporter Ryan Knutson — interviewed from the conference Monday via Skype by NPR's Robert Siegel — says that for some smartphone users, Wi-Fi may be able to replace most of the functionality of a cellphone carrier. Josep Lago/AFP/Getty Images hide caption

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