What's In An Aspect Ratio?

 I recently saw the film, Mommy by French-Canadian filmmaker Xavier Dolan, who used various aspect ratios as subtle visual/narrative device. Most of the film is shot in a 1:1 square aspect ratio, apparently as a metaphor for the narrowed horizons of their lives. In other more jubilant moments it switches to widescreen, and adjusts accordingly to the shifting tensions. The film is terrible