Nearly continuous colour changes rotating around a spectrum, occurring at varying speeds of rotation and in varying values of light. Colours are seen on the scraped area starting nearly white and rotating very slowly. As the film progresses the colour values become darker and the speed of rotation increases until by the end of the film, the colour is nearly black and is rotating around the spectrum about once per second. On the right the opposite occurs, starting nearly black, rotating very slowly. The moment to moment combination of colours and values is a function of the varying rate of rotation.