Mathematicians have found that it is possible to gain full control of sound waves which could lead to improved medical scans, for technology such as ultrasound machines. They tested the numerical properties of a flat lens made out of ‘meta-material’ – a material that gains its properties from its structure rather than its composition. This material is thought to defy the laws of physics, allowing objects to appear exactly as they are rather than upside down as seen in a normal convex or concave lens.