Sculptures composed of soft materials, such as rubber, latex, or cloth. Such works undermine traditional ideas about sculpture, namely that it be durable and made from “noble” materials like marble or bronze. Although artists in the early 20th century, such as Meret Oppenheim, experimented with nontraditional materials (Oppenheim’s 1936 Object consists of a fur-covered teacup), Claes Oldenburg is commonly credited as the originator of the form. Beginning in the late 1950s, he started experimenting with materials like women’s stockings, latex, rubber, and burlap to create everything from toilets and oversized B.L.T. sandwiches to cars and donuts. In the 1970s, many post-minimalist artists, such as Eva Hesse, made sculptures and installations using common materials that were flexible or ephemeral. This was a direct reaction to the assertive, inviolable forms of Minimalism.