This is perhaps the only optical illusion you would want to see while you're driving. A team of university engineers has created a vehicle headlight that adjusts itself so that drivers can keep their high beams on even when other cars are coming toward them. To the driver, the light still looks extra-bright. But from the point of view of the oncoming driver, it's automatically dimmed.
That's not the only thing the prototype headlight is able to do. It's also able to project arrows or lane markers onto the road. It can sense upcoming street signs and shine more light onto them. And it can make raindrops or snowflakes seem to "disappear" from its beam, to clear the vision of the driver—a trick that this team of engineers, from Carnegie Mellon University, has been working on for a few years now.
How does it all work? The headlight is actually made up of not just one beam of light, but one million tiny, individual beams. The individual beams are created the same way pixels on a projector are. There's a semiconductor chip that has an array of a million tiny mirrors on it. The mirrors flip to modulate each pixel's brightness.