This way, the system can turn off some beams sometimes without the driver noticing too much. To make raindrops "disappear," the system tracks falling rain, predicts where the drops are going, and then turns off the beams that would otherwise reflect light off the drops. To make headlights appear dimmer to oncoming drivers, the system tracks other cars and turns off only the beams that are aimed at those drivers. To make arrows on the road, the beams project their light accordingly. It's like having a football field full of dorky marching-band players that you can rearrange into whatever patterns you like. (I was in marching band in high school).