Penny Siopis: Cloud On 30 May 2013, Wits Art Museum (WAM) will host an auction of South African contemporary art in order to kick-start an endowment campaign and to celebrate the museum's first year of operation in the new space. 30 South African artworks have been donated to the museum by major artists including William Kentridge and David Goldblatt. . A ‘Talkabout ’with Senior Curator Julia…