How does the author use symbolism in the novel, The Unhoneymooners?

One example of symbolism can be found in Olive's hideous green bridesmaid's dress, which is representative of her dynamic with her twin sister, Ami. While Olive prefers to stay in the background, Ami enjoys being the center of attention and Olive lets her have it. Even if that means having to wear an unflattering dress. This further demonstrates how Olive would do anything for her sister if it made her happy. While she is embarrassed by how the dress looks on her, she doesn't make a fuss about it to Ami because she wants her sister's wedding day to be as perfect as possible.