The lovely Conversation(s) With Other Women.
"Conversations' innovation in split screen is the juxtaposition of shot and reverse shot of two actors in the same take, captured with two cameras, for the entire movie. The film represents a new kind of viewing experience that enlists the audience as a perceptual editor. The filmmakers allow the viewer to choose how they watch the film, following either character or both simultaneously. Seeing both characters act and react in real time lets the audience follow the emotional experience of the characters without interruption."
I highly recommend it.