What happens when part of a setting is so completely integrated into a story that it magically transforms from a Thing into a Character?
Take this rock wall from a photo I snapped somewhere along one of our road trips. It could simply be part of the setting -- background detail to help ground the reality of where our characters are and what they see, maybe even showing how they feel about it that defines them somewhat. This is the typical use of description, even when it's describing such a gorgeous scene as this wall.
On the other hand, it could become such an important part of the story that the story wouldn't be the same without it. It could be a catalyst for a character to change. Maybe he passes it every day and ponders it for miles afterwards, so much so that it becomes a part of him. Maybe he becomes as rigid and strong as that rock wall while allowing enough subtle growth to let himself flourish like the hardy vegetation hanging on to its side.
I used this device in Finishing Touches, my novel about a young artist fighting against being an artist because she marries one and feels she can't compete with him. Throughout the story, she often refers to the huge window in their loft that allows her to look out at the world while staying safely closed within. To my delight, one of my readers picked up on the characterization of the window and how it helped define Jenna herself. It reflects her struggle to look out or to stay in, her urging to explore her art and use it, or to give in to her insecurity of not being good enough. This theme reaches beyond art and into other areas of her life.
Her artist spouse, who she loses just before the story begins, paints a scene of them wrapped in only a blanket looking out at the river below. The window, here, becomes a metaphor of the exposure Jenna feels because of his professional career, because she becomes known as his wife and attracts another young artist who is a fan of his work. Still, it keeps a boundary. She may be exposed but she's beyond anyone's bounds to be able to reach. Or so she believes.
The window becomes a character. The story would hardly be the same story without it.
[originally posted at Lindsay's Romantics 26 March 09: http://lindsaysromantics.blogspot.com]