A few days before Thanksgiving, George Hotz, a 26-year-old hacker, invites me to his house in San Francisco to check out a project he’s been working on. He says it’s a self-driving car that he had built in about a month. The claim seems absurd. But when I turn up that morning, in his garage there’s a white 2016 Acura ILX outfitted with a laser-based radar (lidar) system on the roof and a camera mounted near the rearview mirror. A tangle of electronics is attached to a wooden board where the glove compartment used to be, a joystick protrudes where you’d usually find a gearshift, and a 21.5-inch screen is attached to the center of the dash. “Tesla only has a 17-inch screen,” Hotz says.

He’s been keeping the project to himself and is dying to show it off. We pace around the car going over the technology. Hotz fires up the vehicle’s computer, which runs a version of the Linux operating system, and strings of numbers fill the screen. When he turns the wheel or puts the blinker on, a few numbers change, demonstrating that he’s tapped into the Acura’s internal controls.

After about 20 minutes of this, and sensing my skepticism, Hotz decides there’s really only one way to show what his creation can do. “Screw it,” he says, turning on the engine. “Let’s go.”

As a scrawny 17-year-old known online as “geohot,” Hotz was the first person to hack Apple’s iPhone, allowing anyone—well, anyone with a soldering iron and some software smarts—to use the phone on networks other than AT&T’s. He later became the first person to run through a gantlet of hard-core defense systems in the Sony PlayStation 3 and crack that open, too. Over the past couple years, Hotz had been on a walkabout, trying to decide what he wanted to do next, before hitting on the self-driving car idea as perhaps his most audacious hack yet.

“Hold this,” he says, dumping a wireless keyboard in my lap before backing out of the garage. “But don’t touch any buttons, or we’ll die.” Hotz explains that his self-driving setup, like the autopilot feature on a Tesla, is meant for highways, not chaotic city streets. He drives through San Francisco’s Potrero Hill neighborhood and then onto Interstate 280. Read full story on Bloomberg.