They do not follow a regular metrical pattern, but they may or may not be rhymed or contain sound patterns. Haiku are usually untitled, and their subject matter usually concerns the natural world. Haiku have become very popular in America in the last several decades. Three-line stanzas tend to be awkward or difficult to manage, especially in longer poems. By contrast, four-line stanzas, or quatrains , have provided the most common strophic organization in English poetry.
Quatrains come in many varieties.
The water, like a witch's oils Burnt green, and blue and white. If lines two and four are lengthened so that the entire stanza consists of tetrameter lines, the stanza is called long measure . When all the lines are of pentameter length, the quatrain is called either heroic or elegaic , depending upon the subject matter treated by the poem and the poem's tone. Another important quatrain is the Sapphic , named so because it was used by the Greek poet Sappho. It has the same ABAB rhyme scheme of the preceding quatrains, but the music of the stanza is very different because one arrives so quickly at the fourth rhyme.