Scientists at Karlsruhe Institute of Technology have developed a method of concealing objects from the sensation of touch that would finally meet the exacting standards of Hans Christian Andersen's fairy tale princess, who felt a single pea prodding her beneath 20 mattresses and 20 feather beds.
The research team's method relies on a metamaterial – a material that exhibits properties not usually found in natural materials – that consists of a three-dimensional polymer microstructure formed by needle-shaped cones. This metamaterial structure is built around the object to be hidden, with its mechanical properties dictated by those of the object.
Cloaking requires that an object be isolated from, and made to externally appear just like, its surroundings for all conditions. In optics, this feat is accomplished with help from an opaque metal wall, and in heat conduction by a thermally insulating wall.