Two years ago researchers at Duke University in the US unveiled the first “invisibility cloak” — a device that can make objects vanish from sight, at least when viewed using a narrow band of microwave frequencies. Now, Ulf Leonhardt of St Andrew’s University in the UK and Tomás Tyc of Masaryk University in the Czech Republic have come up with a new way of using mathematics to describe a invisibility cloak (Science DOI: 10.1126/science.1166332).