“He’s going to beat Wilfred.” “What for?” Robert shook his head doubtfully. “I don’t know. He didn’t say. He got angry and made us tie Wilfred up. He’s been”–he giggled excitedly–“he’s been tied up for hours, waiting–”
This exchange takes place between Roger and Robert the morning after the boys kill Simon in a frenzy. In the aftermath of Simon's murder, the laws of civilization have been completely abandoned, and this scrap of conversation reveals that Jack is already ruling his tribe with senseless cruelty and violence. The fact that he's going to hurt Wilfred for no ostensible reason, and that Robert is giddy about Wilfred's awful fate, highlight that the boys have thrown away any moral code they once had.
The chief was sitting there, naked to the waist, his face blocked out in white and red. The tribe lay in a semicircle before him. The newly beaten and untied Wilfred was sniffling noisily in the background.
This scene shows Jack’s complete transformation into a tyrannical leader who rules through fear and spectacle. His painted face symbolizes the loss of his civilized identity and his embrace of savagery, and the semicircle of boys suggests their submission to his authority. Wilfred’s presence as a freshly beaten victim reinforces the violence and intimidation that Jack uses to keep his tribe under control.
Read more about Jack as the novel's protagonist.
The chief led them trotting steadily, exulting in his achievement. He was a chief now in truth; and he made stabbing motions with his spear. From his left hand dangled Piggy’s broken glasses.
In this scene, Jack has stolen Piggy's glasses. Without them, it's impossible for Ralph’s small group to start fires, which means they have no hope of rescue, and their link to civilization is totally lost. Like Piggy without sight, Ralph’s group is now powerless and vulnerable.