Metaphor is one of the many figures of speech in which it uses implied comparison between two or more things that are not related but with specific similarities. Here are examples:
The rejection I received is another door for a great opportunity ahead. She is the glasses of his eye frame. <span>She has bouncy balls of emotions just by seeing him.</span>
In Mattie's mind, Blanchard's balloon—“a yellow silk bubble escaping the earth”—symbolizes freedom, particularly an escape from her home, where she feels as if she's trapped and treated like a child.