MEMS micro car. Coloured scanning electron micrograph of an experimental MEMS (microelectromechanical systems) micro car in an un-erected state, showing three of the four wheels (round). MEMS devices are constructed on a microscopic scale using technologies such as wet and dry etching and thin film deposition. Applications include sensors and optical displays. Materials used to construct MEMS devices include silicon and polymers such as plastics. Magnification: x285, when printed 10 centimetres wide.