A team of materials researchers at the University of Arizona say they've used 3D printing microfabrication to create materials which can change the way microwaves are refracted. The call them 'metamaterials,' and their design may one day change the way microscopes work and even result in 'invisibility cloaking' which would render the surfaces of such materials invisible to the naked eye. You can read the whole story here: http://3dprint.com/40226/3d-print-invisibility-cloaks/