Norman McLaren became interested in cinematic techniques while studying at the Glasgow School of Art between 1932 and 1937 and spent his spare time making films and playing the organ. His gifts attracted the attention of John Grierson, who offered him a position in the British General Post Office Film Unit when he left the school. McLaren remained with the unit until 1939. About this time he began to experiment with synthetic sound and developed a considerable range of semi-musical effects, mostly percussive.
After working independently from 1939 to 1941 in New York, he joined the National Film Board of Canada (of which Grierson had become the director) and began to develop the innovative animated film techniques that eliminated the camera and required the artist to draw directly on the film. McLaren also created 'animated sound,' a form of 'visible' or synthetic sound made by hand-drawings on the sound-track of the film seen in his films Dots , and Loops . He explains his method in the short film Pen Point Percussion.