(thanks to Sid Fossil for showing me this film!)
“Pas de deux is a 1968 short dance film by Norman McLaren, produced by the National Film Board of Canada.
The film was photographed on high contrast stock, with optical, step-and-repeat printing, for a sensuous and almost stroboscopic appearance. It shows a ballerina (Margaret Mercier) dancing by herself (or rather, with images of herself), before being joined by a male dancer (Vincent Warren), to perform the pas de deux of the title.
The film is choreographed to Romanian pan pipe music.”