Although jazz is mostly an improvisational form, it is easy to detect from its exotic sound its many disparate musical roots. The fundamental syncopation and the common inclusion of a piano and brass instruments—such as the cornet, trumpet, and trombone—suggest the influence of ragtime. The subsequent addition of saxophones stems from the debt jazz owes to dance orchestras. Brass bands were also one of the chief inspirations of jazz's ensemble mentality, whereby all musicians play lead and counter melodies simultaneously. But the most striking features of jazz originate directly from the blues, where musical soloists often mimic the vocals while distorting them using various unique effects. This passage is mainly about: