What does the whirligig symbolize in chapter 6, "Bellevue, Washington," in the book "Whirligig?"

The whirligig comes to symbolize, at first, the constant pressure to succeed that Tony feels from his parents, and then, later, the need for rest. Tony, a Korean boy, feels under tremendous pressure, not only from his parents and teacher to succeed at violin, but tremendous cultural pressure, as an Asian, to be hard-working, polite, and deferential. In this way he resembles Brent; just as Brent was driven by his ambition to be accepted by the popular kids at school, eventually leading to his breakdown and suicide attempt, the pressure Tony is under could also lead him to a similar breakdown—you could think of his disastrous recital as a kind of expression of frustration at this pressure to perform, or as a symptom of approaching mental and emotional exhaustion. Either way, the whirligig he discovers symbolizes his struggle, and permits Tony to "learn" from Brent's experience in that his violin teacher uses the whirligig as a metaphor to explain why taking a break from practice is so important.