Bell pattern
A bell pattern is a rhythmic pattern, often a key pattern (also known as a guide pattern,phrasing referent,timeline, or asymmetrical timeline), struck on an Idiophone, in most cases, a metal bell, such as an agogô, gankoqui, or cowbell, or a hollowed piece of wood, or wooden claves. In contemporary music, bell patterns are also played on the metal shell of the timbales, and drum kit cymbals.
Sub-Saharan African music
Gerhard Kubik notes that key patterns originated within "those parts of Africa where Kwa languages and the 'westerm stream' of the Benue-Congo, or 'Bantu' languages are spoken" [within the larger Niger–Congo-B group]. Use of the patterns has since spread throughout the greater Niger–Congo language family. The use of iron bells (gongs) in sub-Saharan African music is linked to the early iron-making technology spread by the great Bantu migrations. The spread of the African bell patterns is probably similarly linked.
Kubik observes that "at the broadest level," the various key patterns "are all interrelated." Key patterns exist in their own right, as well as in relation to the three inner reference levels of elementary pulsation, main reference beat, and primary cycle. Kubik further states that key patterns represent the structural core of a musical piece, something like a condensed and extremely concentrated expression of the motional possibilities open to the participants (musicians and dancers).