Images, top row, from left: The Enigma, 1998, pen and ink, 12 1/2 x 15 1/2 inches; May Day, 1995, oil on canvas, 20 x 24 inches; Old Chestnut Trees in Luxemburg Garden, 1998, pen and ink, 25 x 31 inches Images, bottom row, from left: The Mantlepiece, 1964, gouache, 15 x 13 1/2 inches; Trees in the Tuilleries and the Jeu de Paume, 1964, gouache, 12 x 17 1/2 inches