All visual art uses light in some form, but in modern photography and motion pictures, use of light is especially important. However, with the invention of electrical artificial light, possibilities expanded and many artists began using light as the main form of expression, rather than solely as a vehicle for other forms of art. Constructivist Naum Gabo experimented with the transparent materiality light reflects on an object; his Linear Construction No. 1 (1943) provides an example of this.[6] Marcel Duchamp's Hat Rack (1916 and 1964), hangs from the ceiling and casts a shadow against the wall.[7]