Well, one thing, when you write the blues and what you be thinking about, you be blue and you ain't got hardly nothing to think about. You just already blue, and you just go and write. It is a story telling form told from the perspective of the African American experience. Blues is a text form. The first line states an idea.
Blues is poetry.
There is a distinct rhyme scheme and rhythmic scansion to the three-line form of text. Usually somewhere around 12-14 syllables in each line, but this can vary substantially. The rhyme scheme features an end rhyme between the first and third line of text. Blues is a musical form. Three chords are used, with a different chord area emphasized in each line of text.