In poetry, a stanza is a group of lines within a poem, usually set off from others by a blank line or indentation. Stanzas can have regular rhyme and metrical schemes, but they are not required to have either. There are many different forms of stanzas, ranging from simple four-line quatrains to more complex forms like the Spenserian stanza. Stanzas are used to provide structure, rhythm, and organization to a poem. They group similar ideas and thoughts together, creating a path for the reader to move from one idea to the next. Stanzas can be arranged according to rhyming patterns and meters, or they can be free-flowing verses that have no formal structure. The stanza in poetry is analogous to the paragraph in prose, as related thoughts are grouped into units. In music, groups of lines are typically referred to as verses.