Four new works of art created by the artist David Hockney on an iPhone and an iPad
"Untitled, 22 July 2010" (iPad drawing) by David Hockney
"Untitled, 22 February 2011" (iPad drawing) by David Hockney
"Untitled, 29 June 2009" (iPhone drawing) by David Hockney
"Untitled, 28 May 2010" (iPad drawing) by David Hockney