KentuckyFC writes "Metamaterials are synthetic substances that can steer light in any way imaginable. Their most famous incarnation is in invisibility cloaks which work by steering light around a region of space making any object inside that region invisible. But invisibility is just the start. A team of physicists in Hong Kong (the same guys who recently worked out how to cloak objects at a distance) have worked out how to create a cloak that makes one object look like another. Instead of steering light to make a region of space look empty, the illusion cloak manipulates light in a way that makes a region of space look as if it contains a specific object. So any object within that region of space, a mouse say, takes on the appearance of an elephant."