In 1966 Carl Andre revolutionized sculpture by pioneering works that lie flat on the ground rather than rising up and occupying space. Andre invites viewers to walk upon his sculptures so that they can register, on a sensory level, the feel of different materials (such as steel and aluminum) and the distinction between standing in the middle of a sculpture and remaining outside of its boundaries. Originally exhibited as part of a single installation entitled 37 Pieces of Work, at the Solomon R. Guggenheim Museum, New York, in 1970, Steel-Aluminum Plain alternates identically sized steel and aluminum plates that form a six-square-foot checkerboard pattern of subdued visual restraint.