Transformation of the corner: A shield cloak and a planar retro-reflector R. Yang, Z. Y. Lei, J. Fan, D. X. Gao, Z. X. Wang and Y. J. Xie EPL, 104 2 (2013) 24004 Published online: 25 November 2013 DOI: 10.1209/0295-5075/104/24004