After meeting the Scottish/Canadian animator Norman Mc Laren at a documentary and animation film festival in Cordoba in 1962, Bras experimented with the technique of "direct scratching on film" by synchronising the image with music and noises. In "TOC TOC TOC TOC" Bras recorded on the optical soundtrack of 16mm film the sound of a pencil tapping against a table. Then, seeing the drawing of the optical sound, he invented graphics that he scratched with the pick of an old phonograph on the veiled film.
