What are the motifs in Confessions of an Ugly Stepsister by Gregory Maguire?

Perception is a recurring idea in thew book. Painters observe the world through color and light. They look for details and qualities some people might miss. Schoonmaker and Caspar both notice something remarkable in Iris, but have to admire Clara for her blatant beauty. Iris is sometimes jealous of the attention Clara receives and even believes Caspar may be interested in Clara. Everyone else can clearly see that Caspar loves Iris, but her perception of self is limited and her insecurity makes her incapable of believing Caspar could love her.