German sculptor and Kinetic artist, born at Lollar, Hesse. After an injury to his hand forced him to abandon plans to become a pianist, he studied at the Academy in Düsseldorf from 1950 to 1953, and then took a degree in philosophy at Cologne University (1956). Early in his career he worked as a painter, but in 1957 he founded the Kinetic group Zero with Otto Piene and since 1958 he has concentrated on working with light. Typically his works use polished aluminium and glass or plastic; irregular movement is imparted to them by an electric motor so as to cause constantly changing light reflections. Mack has used many other kinds of material, however, and his work has included water sculptures and wind sculptures. He is interested in environmental work and has made several visits to the Sahara in connection with his project for a ‘vibrating column of light in the desert’. Since 1968 he has also done stage design. Mack has had numerous public commissions, including a spectacular fountain on the Platz der Deutschen Einheit in Düsseldorf (1988) and has also made book illustrations, including to the poems of Goethe (1999).