A six-line stanza, also known as a sestet, is a group of six lines in a poem. It can follow various rhyme schemes, such as AABCCB or ABABAB, and is often used to develop a specific idea or theme. The structure allows poets to explore complex emotions or narratives within a concise format. Sestets are commonly found in sonnets, particularly in the Petrarchan sonnet, where they follow an eight-line octave. This format encourages a shift in tone or perspective, making it a powerful tool for poets to convey their messages effectively.