A quatrain poem is a poem with four rhymed lines that alternate. As a result, the first and third lines, as well as the second and fourth lines, conclude with a word that rhymes with each other. The quatrain poem can also be written in one of two rhythms: 1,2,1,2 or 1,1,2,2. A quatrain poem usually has fourteen syllables per line, although some poets may choose to use different numbers of syllables per line. The form of the quatrain poem is very popular in Europe and parts of Asia, but it is rarely found in North America. However, several modern American poets have used variations on the quatrain form, including Robert Frost, John Keats, and William Wordsworth. Formal elements of a quatrain poem: - It has four lines that alternately end in weak or strong syllabic units. This means that half of the time, the last line will have two syllables and the first line will have six syllables; the other half of the time, the last line will have four syllables and the first line will have two syllables. - Each line contains an equal number of words (or monosyllabic units). This means that there are either seven or eight words on average in a quatrain poem, depending on how you count the final punctuation mark.