1. The signal fire: A ship or plane has to see the signal fire if the boys will ever be rescued
2. Piggy's specs: Piggy's specs are used to start the fire that can rescue them. He is the only one who has common sense and the ability to reason. As his glasses get destroyed and then eventually taken, this presents a huge loss to Ralph's group, and the prospects of rescue seem dim.
3. The boy's hair: The longer the boys are on the island, the longer their hair grows, and the more rapidly they descend into savagery and lose their innocence.
Theme Statement: When vision becomes cloudy or impaired, the descent from civilization to savagery may occur.