Round, monochromatic, illuminated boxes are attached at the level of the windows on the trains in a subway tunnel. Depending upon the speed of the trains, the different heights and colours of the lights create the impression of a coloured sine wave, which contains all the colours of the spectrum.⁠ ⁠ ‘I only see when I move’, 2001. Previously installed in St. Louis, Missouri in 2001 (photo: Jennifer Dorsey).⁠