Although the imagery of light and darkness is prominent in the story, and darkness is an obvious metaphor for evil, the strength of the book lies not so much in L'Engle's use of figurative language as in the strong visual images she creates. This is particularly apparent in the strange creatures the children encounter in their cosmic travels. On Uriel, for example, when the three ladies take on their beautiful, part-horse, part-man appearance with rainbow wings, L'Engle combines images that appeal to the senses with potent symbolism that underscores the theme. The rainbow is a symbol of hope and divine grace derived from the Book of Genesis, where it is God's sign that he would never again flood the earth as a punishment for man's sins.
Another example is in the description of the beast-like creatures the children meet on Ixchel. L'Engle combines visual, tactile, and aural imagery to create a kind of transcendental reality experienced through the human senses.