BMW has filed a patent with the European Patent Office (EPO) for a "virtual mirror" or to put it in another way, a HUD mirror.

Instead of having mirrors outside the A-pillar, BMW proposes having a kind of semi-transparent mirror on the actual window itself.

Video from external cameras is shown on a display that is reflected onto the window mirror to the driver's eye. The image would appear where a conventional mirror would be, but with the aerodynamic benefit of not having physical mirrors jutting out.