Chunk is one of Richard Serra’s first sculptures based on the act of propping, a concept Serra used in questioning the traditional verticality of sculpture [see the later prop pieces in this exhibition made of lead and steel, including Standpoint (n. 12), Joplin (n. 14) and Corner Prop Piece (n. 28)]. The material for Chunk and many other early rubber pieces is waste Serra found near his studio in New York.     Ellsworth Kelly (b. 1923) Blue Black (2000), Painted Aluminum Panels The Pulitzer Foundation for the Arts Blue Black is an abstract painted wall sculpture. In the previous exhibition, Exploring Ando’s Space: Art and the Spiritual, it was suggestive of heaven and earth. In the context of this exhibition, it resonates with a multiplicity of objects, including Brancusi’s Endless Column and Serra’s geometric forms.