Italian artist associated with Arte Povera, born in Andorno Micca, Piedmont. In 1965 he encountered the work of Pino Pascali, which represented for him an alternative to the ‘rather gloomy’ atmosphere in Italy at the time. He interprets Arte Povera not as the use of rough raw materials but as a kind of materismo. This meant working with materials for their associations and visual qualities with regard to the way they might be transformed by their environment. For instance in Column (1967) there is a mixture of plaster and cobalt chloride which changes colour in response to the humidity, itself affected by the number of people in the room. Spectator participation was also involved in a 1969 installation To Purify Words. The participant spoke through a tube, which then passed the words through alcohol, stimulating flashing headlights. Most dramatic is the Phosphorescent Fist (1971, Pompidou Centre, Paris), a wax model suspended in space which glows bright green when the lights are switched off. The associations with political militancy are surely not accidental.