Current glasses-free 3-D TV prototypes use a static, thinly striped LCD overlay to point images left and right, but such displays have limited viewing angles and can come out looking like cheap holograms. Researchers at the Massachusetts Institute of Technology's Media Lab have refined that technique, replacing the old pinstripe overlay with a matrix of thousands of tiny slits. A processor pre-scans the images to identify the subject of each frame. The system then configures the overlay to match the contours of the picture, so there's the illusion of depth only where it's needed. A Mini Cooper's roof, for example, gains a more pronounced curve.