Minimalism describes art movements that strip works down to their most fundamental forms. Minimalist art from the 1960s-1970s uses simple geometric shapes, industrial materials, and is purged of metaphor. Key minimalist artists include Donald Judd, Agnes Martin, Frank Stella, Carl Andre, and Robert Morris, who were influenced by composers John Cage and LaMonte Young. Donald Judd's sculptures used simple cubes and planes to explore space, while Agnes Martin's grid paintings combined spirituality and minimalism.