Somalis have a rich musical heritage centered on traditional Somali folklore. Most Somali songs are pentatonic; that is, they only use five pitches per octave in contrast to a heptatonic (seven note) scale such as the major scale. At first listen, Somali music might be mistaken for the sounds of nearby regions such as Ethiopia, Sudan or the Arabian Peninsula, but it is ultimately recognizable by its own unique tunes and styles. Modern Djiboutian popular music can be traced back to the late 1940s, Somali songs are usually the product of collaboration between lyricists (midho), songwriters (laxan), and singers (codka or voice). Balwo is a Somali musical style centered on love themes that is popular in Djibouti.