With these may be grouped the music of Sudan and of the Horn of Africa, including the music of Eritrea, Ethiopia, Djibouti and Somalia. Somali music is typically pentatonic, using five pitches per octave in contrast to a heptatonic (seven note) scale such as the major scale. The music of the Ethiopian highlands uses a fundamental modal system called "qenet", of which there are four main modes: "tezeta", "bati", "ambassel", and "anchihoy". Three additional modes are variations on the above: tezeta minor, bati major, and bati minor. Some songs take the name of their qenet, such as tizita, a song of reminiscence.