A quatrain that rhymes abab and alternates four-stress and three-stress iambic lines (each pair equivalent to a single line of 14 syllables), the metre of the hymn and the ballad. An example is "Sir Patrick Spence." Short or half measure consists of a six-stress, 12-syllable line split into two three-stress, trimeter lines. Long measure has eight-stress lines of 16 syllables that are divided into two four-stress lines. An example is T. S. Eliot's "Whispers of Immortality."