Grande ferro M 4 (Large Iron M 4), 1959  Welded iron sheet metal and tacks on wood framework, 199.8 x 189.9 cm  Solomon R. Guggenheim Museum, New York 60.1572  © Fondazione Palazzo Albizzini Collezione Burri, Città di Castello/2015 Artist Rights Society (ARS), New York/SIAE, Rome  Photo: Kristopher McKay © Solomon R. Guggenheim Foundation, New York 