German painter, sculptor and kinetic artist, most of whose works incorporate nails and are painted white.Worked first with regular mathematical sequences of nails, then from 1960 introduced organic structures, and made his first revolving disc-shaped structures and his first light boxes. Experimented with oscillation patterns, with nailed chairs, tables, pianos, with revolving sacks of nails, with ‘light nails’, and from 1966 with high frequency currents, light machines, sand machines, etc., sometimes from 1969 executing large-scale projects in the countryside.