Visual music also refers to systems which convert music or sound directly into visual forms, such as film, video, computer graphics, installations or performances by means of a mechanical instrument, an artist's interpretation, or a computer. The reverse is applicable also, literally converting images to sound by drawn objects and figures on a film's soundtrack, in a technique known as drawn or graphical sound. Famous visual music artists include Mary Ellen Bute, Jordan Belson, Oskar Fischinger, Norman McLaren, John Whitney Sr., and Thomas Wilfred, plus a number of contemporary artists.