Rhytmus 21 by Hans Richter
German artist, writer and filmmaker Hans Richter's first film
Rhytmus 21 (1921) was first shown in public on July 6th 1923 in France, showcasing his experiments with moving geometrical shapes and explorations between positive and negative space. The original film was actually silent and it was extended over the years and renamed as Rhythmus 23, and Rhythmus 25 according to the year it was re-released (1923 and 1925 respectively).
One of our readers was kind to correct my previous info, so here it goes:
"The original film was roughly two minutes long. Over the next two years Richter worked on the film and extended it to almost seven minutes. Before October 16th, 1927 when the film was screened at the Film Society in London, Richter divided the film in two parts and later on called it Rhythmus 21 and Rhythmus 23. In the following year Richter created another chapter, Rhytmus 25, which didn't survive."