Afro rock is a popular dance music pioneered in the late 1960s and early 1970s by such groups as Monomono, Osibisa and Alhaji K. Frimpong. It is a style of which relies heavily on the use of Western string instruments (electric guitars and bass) and guitar effects. The genre is deeply based in Western chordal structure and progression (mostly minor), emphasized on instruments like synthesizer and organ. Although the rhythmic engine of the music is (some configuration of) a western trap set, other characteristically African and Afro-Cuban elements pervade the remainder of the rhythm section (including congas, claves, shekeres, bells, and whistles). The vocal style can be seen as an amalgamation of African language and inflection into an American rock and funk context.