The most distinctive component of African music, however, is the focus on the rhythm. In this respect, African folk styles are far more complex than anything developed anywhere else in the world. African music is usually polyrhythmic, made by a wide variety of percussion instruments, both pitched and unpitched, using numerous kinds of natural materials. Polythythms were imported along with slaves to the New World, where it has found its way to genres ranging from African American gospel to pop-swing and rock and roll.