In the past year, triangular love stories have loomed large in cinema - Past Lives, Challengers and Passages all had different angles on the spiky geometry of three-cornered relationships.
Since Casablanca, these complicated love affairs have fascinated filmmakers and audiences alike. They can be the subject of romantic comedies, at the centre of a melodrama or the motive for murder in a thriller - the relationships can be gay or straight and the budgets big or small.
Jean Luc Godard’s iconic new wave robbery tale Bande à part is 60 this year. It seems that each generation has its iconic love triangle movie - The Philadelphia Story, Sabrina, The Graduate, Blood Simple, Y Tu Mama Tambien, The Notebook and My Best Friend’s Wedding - the films could not be more different but the dynamics are always rich and provocative.
Mark Kermode and Ellen E Jones ask where love triangles have taken us over the years and how they reflect the sexual politics of the times.
Guest interviews include Ira Sachs, director of the acclaimed Passages, and writer and critic Anne Billson.
Producer: Tom Whalley A Prospect Street production for BBC Radio 4