How does the author use imagery in the novel, Alias Grace?

Atwood makes full use of her talent for sensual imagery, at times creating an almost psychedelic synaesthesia, i.e. an especially effective blending of images that appeal to more than one of the reader's senses. For example, at the beginning of the book, Grace describes peonies that are blooming amid the gravel of a prison walkway: "They come up through the loose grey pebbles, their buds testing the air like snails' eyes, then swelling and opening, huge dark red flowers all shining and glossy like satin."