In 2014 internet users stumbled onto a YouTube channel called Webdriver Torso that had quietly uploaded more than seventy thousand videos. Every one was identical: eleven seconds long, a blue rectangle and a red rectangle blinking on a white screen, each frame marked by a flat electronic beep. The videos carried no titles or descriptions, and the account behind them was anonymous.
The internet went hunting for meaning. To some, it looked like a numbers station, the coded shortwave broadcasts spies use. Others were sure it was a signal meant for extraterrestrials, or a hidden piece of Cicada 3301. Still the videos kept coming, thousands of them, day after day.
The answer came from YouTube itself. Webdriver Torso was its own creation, a robot account that uploaded the rectangles by the thousand and measured how badly the shapes and colors degraded after compression, a quality test running in the background of the world's biggest video site. Its makers had even hidden a joke inside: among the identical clips sits one where the red rectangle flickers, for a second, into the silhouette of Rick Astley.