Dan Flavin, untitled (in honor of Harold Joachim) 3, 1977, pink, yellow, blue, and green fluorescent light, 8 ft. (244 cm) square across a corner. Photo: Billy Jim. Courtesy Dia Art Foundation. © Steven Flavin/Artists Rights Society (ARS), New York.

Dan Flavin (1933-1996), The diagonal of May 25, 1963 (to Constantin Brancusi), 1963, Edition 3/3, yellow fluorescent light, 8 ft long on the diagonal. Dia Art Foundation. Photo Billi Jim, Courtesy Dia Art Foundation. © Steven Flavin/Artists Rights Society (ARS), New York.

Dan Flavin, "untitled (to you, Heiner, with admiration and affection)," 1973. Green fluorescent lightmodular units, 4 ft. (122 cm) high, 4 ft. (122 cm) wide, length variable. Photo: Florian Holzherr. Courtesy Dia Art Foundation. © Steven Flavin/Artists Rights Society (ARS), New York.

Dan Flavin, "the nominal three (to William of Ockham)," 1963. Cool white fluorescent light. 8 ft. (244 cm) high. Photo: Billy Jim. Courtesy Dia Art Foundation. © Steven Flavin/Artists Rights Society (ARS), New York.