Ruben Östlund points to his own “triangle of sadness.” Spoiler alert: The following interview addresses plot twists and details of “Triangle of Sadness,” including the ending. When Swedish filmmaker Ruben Östlund won the top prize at this year’s Cannes Film Festival for “Triangle of Sadness,” it put him in the rarefied class of two-time Palme d’Or winners. Of the first …
