This is similar to the character psychoses and the location themes but covers recurring plot themes that are not character or place dependent.
These are metaphorical themes that run throughout your novel and add another artistic layer to your text.
They fall into two categories:
Natural themes
These are themes that you notice have occurred in you novel naturally as
you have written it.
In Nix Ex Machina, I looked through the plot and noticed that the resting places of the dead being disturbed was a recurring theme:
Having noticed this theme, I then adopt it as a metaphorical theme and use it elsewhere to reinforce it:
Engineered themes
These are themes that you consciously decide to insert into your novel. Tarko
gets caught between two rival gangs and so is like a pawn on a chess
game. I decided that this was a nice analogy and so wanted to have chess
flow throughout the whole novel as a metaphorical theme:
In Pulling Power, there is a recurring theme or people staring into light. Eve stares at the sun in the Californian desert, when coming round in the hospital Matt stares up at the ceiling light, an FBI agent stares at another ceiling light when sliding in through an open window on his back.