Blues music is based on an ABAB pattern standard.
 Shuffle rhythm is often vocalized as "dow, da dow, da dow, da" or "dump, da dump, da dump, da": it consists of uneven, or "swung", eighth notes
Blues has evolved from the unaccompanied vocal music and oral traditions of slaves imported from West Africa and rural blacks into a wide variety of styles and subgenres, with regional variations across the United States

