Snapshots of electric field patterns, with stream lines [black lines in (A–C)] indicating the direction of power flow. The cloak lies in the annular region between the black circles and surrounds a conducting Cu cylinder at the inner radius. The fields shown are (A) the simulation of the cloak with the exact material properties, (B) the simulation of the cloak with the reduced material properties, (C) the experimental measurement of the bare conducting cylinder, and (D) the experimental measurement of the cloaked conducting cylinder. From reference [48]. Reprinted with permission from AAAS.