As a retrospective of her work opens in London, Rainer looks back at her journey from experimental choreographer to anarchic film-maker and back again Yvonne Rainer is the iconoclastic choreographer who, beginning in the 60s, pioneered the deconstruction of modern dance in a manner closely associated with minimalist art. No Manifesto, published in 1965 ("No to spectacle. No to virtuosity. No to transformations and ma…