Her later work - she cannot control her left hand as well as she did her right - tends to be less intricate and more abstract. Much of it - such as One in 100 Billion - is based on neurons and brain imagery, which has fascinated her since she saw her own brain angiogram, an X-ray image of cerebral blood vessels. She also makes frequent use of symbols from "The Lesser Key of Solomon," an anonymous 17th-century mystic tract.