"Auxetics" comes from the Greek word auxetos, meaning "that which may be increased". In this report, the term 'auxetic' will be used. People have known about auxetic materials for over 100 years, but have not given them much attention. This type of material can be found in some rock and minerals, even animal such as the skin covering a cow's teats. To date, a wide variety of auxetic materials has been fabricated, including polymeric and metallic foams, micro porous polymers, carbon fibre laminates and honeycomb structures.