In the short story "The Wish" by Roald Dahl, a young boy merely needs to cross a carpet to the front door and go outside where his mother is waiting for him. However, this child has a lively curiosity and intense imagination. In his mind, the carpet before him comes alive with imagery. He becomes a hero in a sort of mythic quest, and the carpet becomes a metaphor for the challenges he faces in pursuit of his goal, which he envisions as a puppy for his birthday present.
The first image Dahl presents is the scab. Because of the boy's overwhelming curiosity, the scab represents "a special challenge he was never able to resist." This is his first metaphorical obstacle, and he becomes determined to pick the scab "even if it hurts like anything." The initial success concerning the scab gives the child confidence and gives him the self-image of a hero, so he looks for a greater challenge.
He then focuses his attention on the carpet. In his imagination "all of a sudden the colors seemed to brighten mysteriously and spring out at him in a most dazzling way." The carpet then becomes a metaphor for the challenges the boy faces in his life. The red spots seem to be hot coals, which can burn and destroy him. The black sections are writhing poisonous snakes, which represent evil, lies, and temptations. Although the child is frightened, he accepts the challenge and begins. Dahl describes the boy's journey across the carpet through the child's perspective, as if the images he has created in his mind are real and he is really in danger. In a sense, this is how fantasies sometimes seem to imaginative children. In a metaphorical sense, the boy's apprehension in traversing the carpet represents the apprehension he will feel while growing up as he faces real obstacles in his path to maturity.
Ultimately, Dahl leaves it up to readers to decide whether the boy falls harmlessly to the carpet or is overcome by his dark fantasies. This is the final ambiguity, which is intentional on Dahl's part, because life, especially to imaginative children, is so often uncertain and frightening.