Previous ImageNext Image Heinz Mack, Otto Piene, and Günther Uecker, “Lichtraum (Hommage à Fontana)” (1964) Heinz Mack, Otto Piene, and Günther Uecker, “Lichtraum (Hommage à Fontana)” (1964), as installed at the third Documenta in Kassel, 1964 Courtesy of the website of the ZERO Foundation, Düsseldorf x x