 This practice was already well-established in earlier jazz, but came to be central to the bebop style.The style made use of several relatively common chord progressions, such as blues (at base, I-IV-V, but infused with II-V motion) and 'rhythm changes' (I-VI-II-V, the chords to the 1930s pop standard "I Got Rhythm").Late bop also moved towards extended forms that represented a departure from pop and show tunes.