Conceptual artist Piero Manzoni, an enfant terrible of Italian art in the 1950s and early 1960s, is best known for Artist's Shit (Merda d'artista) (1961), 90 sealed cans priced by their weight in gold, one of many works that question the nature of the art object. Other stunts included balloons filled with "artist's breath" and “Living Sculptures,” human subjects signed by Manzoni. His “Achromes” paintings (from 1957 onward), canvases covered in materials like gesso, kaolin, fabric, and bread that undergo sagging, creasing, and other temporal changes, suggest the influence of Yves Klein and Robert Rauschenberg.