the slow movements by contrast are united only by their diversity. the violin and keyboard play different roles and there are often more than two voices in the upper parts, which can divide in the keyboard part or have double stopping in the violin. bach explored all possibilities in the slow movements: they can resemble movements from every variety of baroque musical genre, including concertos, chamber works, dance suites, cantatas or accompanied arias; and the textures in the keyboard and the violin were often new departures, quite distinct from previously known compositions.