Oliver Paul at the University of Kaiserslautern in Germany and associates have revealed a practical way of making invisibility cloaks of any size and shape, The Physics ArXiv Blog reports.

Creating a cloak that exactly follows the shape of the object it is intended to hide is hard because curve cloaks are hard to make, so they approximated the shape using flat facets.

Ref: Oliver Paul, Yaroslav Urzhumov, Christoffer Elsen, David Smith, and Marco Rahm, Flat-Face Approximations Of Invisibility Cloaks With Planar Metamaterial Layers, arXiv, arxiv.org/abs/1110.5604