The Aground Whale-shark is a reflective poetic form concerning rain, originating in The Cooperation of Umbras. The form guides poets during improvised performances. The poem is an extremely long series of quatrains. A form of parallelism is common throughout the poem, in that certain lines reverse grammatical structures. The third line of each quatrain is required to maintain the phrasing of the second line. The third line of each quatrain reverses the word order of the second line. The fourth line of each quatrain presents a different view of the subject of the second line.