Explain how characters with deformities are used in literature according to Foster.

From the text:

Things have changed pretty dramatically in terms of equating scars or deformities with moral shortcomings or divine displeasure, but in literature we continue to understand physical imperfection in symbolic terms. It has to do with being different, really. Sameness doesn’t present us with metaphorical possibilities, whereas difference – from the average, the typical, the expected – is always rich with possibility.