Polysyndeton:
Sentence that uses and or another conjunction to separate the items in a series. Polysyndeton appears in the form of X and Y and Z, stressing equally each member of the series. It makes the sentence slower and the items more emphatic then in the asyndeton.


Example:
"Let the white folks have their money and power and segregation and sarcasm and big houses and schools and lawns like carpets, and books, and mostly--mostly--let them have their whiteness." 

- I Know Why the Caged Bird Sings: by Maya Angelou

Explanation:

The reason Maya Angelou does this is for one main reason. One reason she does this is to show ALL the things that the white people had. The emphasis on everything they have shows that this is unlike what the black people had at the time. The reader sees this, and has sympathy for Angelou and other African Americans.