What is an example of symbolism in Chapters 30 and 31 of To Kill a Mockingbird by Harper Lee?

Boo is used as a symbol of innocence and purity in Chapter
31. Scout mentions his extreme "whiteness," a color that is symbolic of both purity and
innocence. He also represents the children's guardian angel, and when Boo touches Jem's
hair, it is as if he is transferring his power of good--of healing--to Jem, a sure sign
that he will survive his injuries. In addition to fulfilling Scout's long unfilled
fantasy--of actually meeting and speaking with Boo--he helps to make the evening one
in which she is able to enjoy a feminine, "ladylike" moment: that of being accompanied
by a gentleman as they walk down the street.

readability="8">

... if Miss Stephanie Crawford was watching from
her upstairs window, she would see Arthur Radley escorting me down the sidewalk, as any
gentleman would.

The street
lights symbolize a kind of enlightenment for Scout who, under their "fuzzy" glare,
glimpses a new and unique view of her neighborhood. She stands on the Radley porch as if
she were standing in Boo's skin--"in his shoes"--seeing the events of the past two years
as if she were reliving them from his own eyes.

One of the
characters from Jem's book, The Grey Ghost, from which Atticus is
reading, features a character named "Stoner's Boy." Stoner's Boy serves to symbolize
Boo, a character who was accused of many things but was proved to be innocent, and in
the end,

    
"... when they finally saw him, why he hadn't done any of those things... Atticus, he
was real nice."
     "Most people are, Scout, when you finally see
them."