German-Swiss-Icelandic artist Dieter Roth (1930 – 1998) used natural materials like chocolate, cheese, bananas, sausages and rabbit dung to make sculptures and images that would blossom with new life as they aged. Here, assistants create chocolate casts of Roth’s famous chocolate or sugar self-portrait busts, as seen on the pallet. (At Chelsea’s Hauser & Wirth through April 13th).