It looks like self-driving cars are the future, doesn’t it? Studies have suggested traffic would be quicker to navigate with a robot behind the wheel instead of humans, andriverless cars are getting better at understanding real-world environments, too, thanks to Grand Theft Auto. That said, they are definitely the future, as in not the present, because they’re not quite ready yet. Self-driving cars are already out there running red lights, and beyond things that like, there are serious ethical concerns to address.

Now, we can sadly add another point to the loss column, since British artist James Bridle demonstrated just how easy it is to trap a self-driving car, preventing it from going anywhere with just what looks like a bag of flour.

We don’t know precisely how the technology involved with self-driving cars works, but it seems simple enough to explain here. They’re equipped with a lot of cameras and sensors, and the job of some of those is to look at road lines to help the car figure out where it should and should not drive. Dotted white lines can be crossed, while solid white lines shouldn’t be.

If that’s a core part of the car’s logic, then tripping it up can be easy, as the video above shows. Just draw a white dotted circle surrounding a white solid circle. The car will drive through the dotted line, but by the time it processes that solid lines aren’t to be messed with, it finds itself surrounded by solid white on all four sides.

In the video, you can even see the car trying to think through this situation, nudging forward a little bit, looking for an escape but finding none. Although this test is artistic in nature, it raises a good point: Driverless cars can be pretty easy to mess with, so perhaps they’re not quite ready for prime time, at least until wrinkles like these are ironed out.

Featured Image: stml