This was the birth of Afro-Cuban jazz. The use of clave brought the African "timeline", or "key pattern", into jazz. Music organized around key patterns convey a two-celled (binary) structure, which is a complex level of African cross-rhythm. Within the context of jazz, however, harmony is the primary referent, not rhythm. The harmonic progression can begin on either side of clave, and the harmonic "one" is always understood to be "one". If the progression begins on the "three-side" of clave, it is said to be in "3–2 clave" (shown below). If the progression begins on the "two-side", it is in "2–3 clave".