Lear creates his atmospheric nonsense land both through sound and imagery. The rattly, grumbly sounds of place names like the "Chankly Bore" and the "great Gromboolian plain" suggest a stark, rocky landscape—an impression that Lear underscores when he describes the scene. "Angry breakers roar / As they beat on the rocky shore," "Storm-clouds brood" over the hills, and an "awful darkness and silence" hangs over it all; this is an unhappy, forbidding landscape.
In the "vast and gloomy dark" of this place, the Dong's luminous nose thus stands out, its light a "lonely spark with silvery rays" that shoot through the "coal-black night." As his nose-lamp "sparkles,—flashes and leaps," it strikes a hopeful contrast with all that darkness—though it's also "lurid" and harsh, reflecting the tragic madness in the Dong's futile quest.
Against this backdrop of brooding shadows and sharp silvery light, the Jumblies offer a brief, poignant flash of color. As they often sing of themselves, "Their heads are green and their hands are blue"—or, as the Dong observes of his beloved Jumbly Girl, "sea-green" and "sky-blue," colors that evoke a happier, livelier natural world than the stormy, rocky one the Dong inhabits. Alas, a flash of a "pea-green sail" is the last colorful thing the Dong sees as the Jumblies leave his land.
Perhaps a longing for this lost color and light shapes the design of the Dong's nose. "Of vast proportions and painted red," the nose is the antithesis of all the shapeless, lumpen darkness the Dong wanders through; its brightness is both sad and defiant.