This sometimes happens in films and television dramas when the screen is split into a number of sections with mini narratives going on in each section.
The film (500) Days of Summer uses a split screen sequence to show two versions of events at the same time.
This occurs when Summer (Zooey Deschanel) invites her ex, Tom (Joseph Gordon-Levitt), to a house party: the left-hand side of the screen displays Tom's imagination of how the evening should go, but on the right side, we watch as the reality of Tom’s evening turns out quite differently.
This is the most complex of all narrative structures with many narratives interwoven as the media text progresses.
This challenges audiences and keeps them curious about how the many narratives will develop. This type of narrative tends to have complex characters that are ambiguous which creates tension and mystery.
A good example of this type of flexi-narrative would be the crime drama, River.
Over the course of six episode series we see DI River try to solve the murder of his colleague Stevie.
In each episode DI River has other cases to solve which are interwoven with the original case.
The audience is also challenged by hallucinations which DI River suffers from, creating a thrilling sense of confusion as to what is real and what isn't.