Since the early 1960s, Franz Erhard Walther has explored the possibilities of objects and images that prompt viewers to do something other than just look. An inspirational to John Bock as a student at Hamburg's Hochschule für Bildende Künste, Bock's work - in the spirit of Walther's - transforms action, speech and everyday materials into complex installations. The two artists discuss the potential of doing things with - and amongst - art.