Spheres Angleiron (1977) iron and steel 18 inches in diameter Robe welded steal 7 inches in diameter Traveler welded bronze 28 inches in diameter TRW #2 welded bronze sphere 15 inches in diameter Moroccan welded steal 7 inches in diameter Untitled Sphere (1989) welded and forged copper 7 inches in diameter Sphere within a Sphere welded and forged steel 9 x 8 x 8 inches Screwball (1982) welded steel 12 inches in diameter Mark welded bronze sphere 15 inches in diameter Halo Ball welded and forged steal 5 x 4 x 4 inches Nuts and Bolts welded steel 13 inches in diameter Octoball (1976) iron and steel 18 inches in diameter White Phosphorus (1982) welded steel screws 15 inches in diameter