What is an example of synecdoche in "lord of the flies"?

In Chapter 4 of the novel, Jack furthers his role as a predator by creating a mask for himself. As he makes it, his obsession blocks out those around him, and the mask swallows up his identity, liberating Jack from "shame and self-consciousness". Jack uses the mask to frighten some of the other boys, and they begin to see only the mask and not Jack. In fact, the mask section closes with the statement, "The mask compelled them", demonstrating that a part (the mask) has actually taken over the whole (Jack). It not only changes how Jack views himself, but it also begins to change the boys' view of Jack.