I took this picture just outside the Place Stanislas in Nancy, looking into what is said to be the most beautiful square in the whole of France. It was designed by Emmanuel Héré and lavishly embellished by Jean Lamour, whose wrought iron archway draws the eye into my photo.

I’m a crap photographer, but I like the way the dark green foliage in shadow at the front of the picture anticipates the lighter tree in the square, and then the one that we can glimpse beyond that. I like the contrast between the pale sky and the gilded filigree of the railings, between the harshness of the foreground and the softness of the distant spire. Really, I suppose, it’s two separate images, ones superimposed on the other, both of them echoing and resonating together.

Just as I’ve attempted to frame one view with another, so one story can provide the setting for another when you are writing fiction. You can do this through flashback, using the present as a lens through which to view of the past, or you can use your subplot, making the actions of the minor characters provide a commentary on the behaviour of your protagonists. As with my picture, there should be plenty of similarities and contrasts between the two layers in your story, in order to make what can sometimes be a complicated process worthwhile. If you can pull it off, your narrative will have greater depth, more nuance, more subtlety than it would if it consisted of a single plot strand, rather than two inter-related ones that counterpoint each other.