Cloaking and wave analogies: water waves, [23] and also microwaves and sound waves [24], experiments have all been performed with the same geometrical cloak. The metamaterial cloak works over a finite interval of wave wavelengths that do not exceed the cloak's diameter (20 cm) and for which the cross-section of its structural elements can be considered small enough (not exceeding one third of the wavelength); (A) microwave experiment (courtesy of R. Abdeddaim and E. Georget, Institut Fresnel) showing both reduced field in the centre of the cloak and cloak's transparency for a transverse electric wave at 3.5 GHz [24]; (B) artistic view of a seismic cloak (Institute Fresnel/INSIS/CNRS); (C) photo of the fabricated aluminium cloak (courtesy of S. Enoch).