Alongside a mixed media list that includes water, injection-molded tiles, solenoid valves, and pressure regulators, Random International’s <i>Rain Room</i>, which opened at London’s Barbican Centre in October 2012, made use of “custom software” and “3D tracking cameras.” Photograph: Rain Room Installation image © Felix Clay, Rain Room – Random International 2012, Courtesy of Barbican Art Gallery. Banner image: A video still from Pipilotti Rist’s <i>Mercy Garden Retour Skin</i> (2014) audio video installation. Banner photograph: © Pipilotti Rist, Courtesy the Artist, Hauser &amp; Wirth, and Luhring Augustine; Mark Metcalfe/Stringer/Getty Images