One of the most important and influential art styles of the 1960s, Minimalism identifies works of art most often comprised of geometric shapes in simple arrangements and lacking any decorative or dynamic flourishes. These geometric shapes characterized the elemental or “bare bones” forms of art, which, according to critics, represented the culmination of modern art's progression toward the most simplified form of abstract art possible. Donald Judd, Dan Flavin, and Carl Andre are among the best-known artists associated with Minimalism, which is characteristically associated with sculpture rather than painting. Minimalism’s roots arguably lie in Russian Constructivism, the paintings of postwar American artists such as Barnett Newman, Ad Reinhardt, and Frank Stella, and the formalist theories of Clement Greenberg. Initial labels for Minimalism—none of which became popular—were "ABC Art" and "Primary Structures" (the latter was the title of one of the first organized exhibitions of Minimalist works).