A car in China just wrote a birthday message on a parking garage wall using nothing but its headlights. Meanwhile your car's headlights are stuck in 1967. Legally. The tech is Huawei's XPixel. Each headlight packs over a million tiny mirrors on a DLP chip, the same chip family that runs movie theater projectors. You scribble on the center screen with your finger and the car draws it on the wall in light. It can also throw a 100-inch full-color movie, paint lane-change arrows onto the road…