Mikala Dwyer, An Apparition of a Subtraction, 2010. Detail. Sandstone, audio, speakers, acrylic, copper, pigface, light, Mor-Mor, wooden plinth made by Les Corben, dimensions variable. Installation view of the 17th Biennale of Sydney (2010) at Cockatoo Island. Courtesy the artist, Anna Schwartz Gallery, and Roslyn Oxley9 Gallery, Sydney. Photograph: Ben Symons.