What metaphors are used in The Star by Arthur C. Clarke?

In Clarke's story, the vision of the children on the seashore is detailed and concrete. Clarke's children, like the nature which surrounds them, cannot be appropriated as metaphors for the self. They are (or were) real, and the narrator remembers them only because he actually saw them on a filmstrip. Clarke underlines the otherness of the vision: these children are not human, and the concrete details of the "strange blue sand" and "curious whiplike trees" and the unknown "large animal" indicate the narrator's distance from the children and nature.