The usual rules of physics don't apply in the laboratory run by David Smith and Sheldon Schultz of the University of California at San Diego. But in Smith's and Schultz's world, things happen backward. When microwaves pass through this material, their physical properties get flipped.
Individual waves move backward even as the overall pulse of microwave energy travels forward.
That the sort of effect caused by this material. In theory, a much smaller, submicroscopic array of wires could perform the same tricks on visible light. For example, light rays passing through the material would bend inward and focus to a point, not spread out as they normally do. Until recently, physicists doubted such a material could exist. Or you could make a better antenna, better filters, or better absorbing materials.