A row of twelve glass spheres, supported at eye level by a black steel frame, changes in appearance as the viewer walks along the row. Depending on the angle of view, each sphere appears to be clear, black, or filled with a vivid colour. Beginning with violet, the spheres progressively present the colours of the spectrum, ending with red. The viewer cannot, however, see an overview of all the colours together at the same time – as she passes by, the colour disappears and the sphere becomes glossy black. The appearance of the spheres is unstable, slipping between clarity, colour, and blackness in response to the slightest movement of the viewer.