Piero Manzoni, Achrome, c. 1960. Cotton wool in squares 21 x 29 cm / 8 1/4 x 11 3/8 in 37 x 45 x 4.5 cm / 14 5/8 x 17 3/4 x 1 3/4 in (framed). Courtesy Fondazione Piero Manzoni, Milan and Hauser & Wirth © Fondazione Piero Manzoni, Milan