Another popular genre of Dutch music is known as "Levenslied", meaning "Song of/about life". These songs have catchy, simple rhythms and melodies, and are always built up on choruses and verses. Themes are often sentimental and include love, death and loneliness. Traditional Dutch musical instruments such as the accordion and the barrel organ are essential to levenslied, though in recent years many levenslied artists also use synthesizers and guitars. Artists in this genre include Koos Alberts and the late André Hazes and Willy Alberti.