First drawn by: Kazuko Miyamoto First installation: Panza di Biumo residence, Varese, Italy, June 1980      Sol LeWitt’s wall drawings are executed by professional draughtspeople from sets of instructions generated by the artist. LeWitt emphasised the idea or concept of an artwork over its visual realisation, hence his assertion that his instructions are themselves the work of art. ‘Wall drawing #337’ and ‘Wall drawing #338’ exemplify this process: both works are drawn by professional draughtspeople following LeWitt’s instructions. The artist’s methodology has been likened to that of a composer: the works are manifested by others, and no single drawing is ever the definitive version. In a 1971 interview LeWitt commented: ‘I try to make the plan specific enough so that it comes out more or less how I want it, but general enough that [the draughtspeople] have the freedom to interpret. It’s as though I am writing of piece of music and somebody else is going to play it on the piano.’