Billy Apple® Double Rainbow, 1964,
Eight-coloured 12 mm clear and fluorescent glass tubing pumped with argon/neon/mercury gas, two parts, 171 x 154 x 15 cm, 67 3/8 x 60 5/8 x 5 7/8 inches
Collection Museum Voorlinden, Wassenaar, The Netherlands
Photo: Antoine van Kaam