A Colour Box is regarded as the first preserved handpainted film. Painting directly onto unexposed film material is a radical version of animation, as no camera is used. The direct contact between hand and film strip gives rise to splotchy shapes and wobbly lines that seem to dance in rhythm to an extremely lively melody (Don Barreto and his Cuban orchestra). In contrast with other works of visual music, Lye’s choreographed abstract shapes are not strict synchronizations, but free renderings of music into images. The film was purchased in 1937 by John Grierson for the advertising film department of the British General Post Office (G.P.O.), which then paid for the production costs. In return, Lye added the advertisement slogan