Fire Imagery
While stationed on patrol at the ammo dump on the night of July 4th, the three soldiers (Philip, Lewis, and Hubbard) become aware of a nearby fire. This fire endangers their lives, as if a spark entered the ammo dump, all the explosives would ignite and blow them all up. There is a lot of apt imagery surrounding this fire, including descriptions of the smoke, the insects fleeing the fire and filling the sky, and the possibility that the main characters could explode in a fiery inferno at any second. This imagery represents the terrifying possibility that life could simply end any second, or that tragedy might strike anyone at any time, being a reality for many people in the world at this very moment.
Violence Imagery
Philip is a paratrooper stationed in the army barracks, so there is naturally a lot of imagery that relates to war, such as descriptions of weapons, beatings, missions, and the war in Vietnam. The nonviolent protest also threatens to break out into violence, and people have to be restrained. This undercurrent of violence is present throughout the novel, and occasionally it comes out in the imagery.
Lewis's Hand
While on patrol duty at the ammunition dump, Lewis sustains an injury to his hand caused by the sharp nettles. It gets infected, swelling enormously and turning an angry red. This particular piece of imagery is a recurring one through the novel, and it represents Lewis's need for human connection. When he connects with the doctor, the lotion calms the angry swelling, but when he turns his back on that weakness and shatters the bottle, it presumably comes back, a painful visual reminder of his peculiar mental condition and human needs.
The Bicycle
When Philip visits his father to confront him about his traumatic visit to their house, his father attempts to give him a folding bicycle as a gift, saying that Philip will have the ability to travel away at any given moment. This bicycle is a physical representation of Guy's own life; he is always ready to leave what he has in search of something new, giving in to his inner restlessness, so he essentially lives with a folding bicycle in his heart. When demonstrating the bike to his son, he ends up tangled on the floor, a symbolic image of the detrimental effects of such a life.
