Barbershop music in tags or codas, or when some appropriate embellishment can be created. One characteristic feature of barbershop harmony is the use of what is known as "snakes" and "swipes." This is when a chord is altered by a change in one or more non-melodic voices. Occasional passages may be sung by fewer than four voice parts. Barbershop music is generally performed by either a barbershop quartet, a group of four singers with one on each vocal part, or a barbershop chorus, which closely resembles a choir with the notable exception of the genre of music. According to the Barbershop Harmony
Homer's Barbershop Quartet and his sister Lisa notice a picture of their father, Homer, on the cover of an old LP album. Homer explains to his family that he, Principal Skinner, Barney Gumble, and Apu Nahasapeemapetilon recorded a barbershop quartet album in 1985, which catapulted them to national fame. He narrates to his family the story of how the band formed, reached the pinnacle of success, and eventually folded. At the end of the episode, the group reunites to perform a concert on the roof of Moe's Tavern, singing their number-one hit "Baby on Board". Throughout the episode, several references are made to