Based on the shape of the human spine this sculpture forms a tribute to Diane Maclean's late father, a surgeon and medical artist. It is a typical example of this artist's love of mixing organic and man-made themes, where the method of construction forms an integral feature of the work. The colours of Spine are produced on its stainless steel surface through a complex chemical process in which each sheet is dipped into tanks of oxide. This adheres itself to the metal in varying degrees of thickness, according to the quantity of oxide that is used. When natural light falls upon the surface, a rich colour spectrum is revealed. The appearance of the sculpture changes with the time of day, season and weather, as well as the shadows that are reflected upon it. Spine's iridescent colours echo the intense tones seen in the natural world, allowing the sculpture to become visually softened, natural and beautiful.