Focus incorporated and articulated jazz-style chords, and irregular off-beat drumming into their later Rock based Riffs, and, several bands that included jazz-style horn sections appeared, including Blood, Sweat & Tears and Chicago. Of these, Martin highlights Chicago in particular for their experimentation with suites and extended compositions, such as the "Ballet for a Girl in Buchannon" on "Chicago II". Jazz influences appeared in the music of British bands such as Traffic, Colosseum and If, together with Canterbury scene bands such as Soft Machine and Caravan. Canterbury scene bands emphasised the use of wind instruments, complex chord changes and long improvisations. Martin writes that in 1968, "full-blown progressive rock" was not yet in existence, but three bands released albums who would later come to the forefront of the music: Jethro Tull, Caravan and Soft Machine.