Doo-Wop emerged from East Coast cities in the 1950s, where groups of teenagers gathered on street corners to make primarily vocal music. Many of these teens were Italian or African American, and their music expressed the pains and joys associated with coming of age in the inner city. Doo-Wop groups relied on soaring vocal acrobatics and the most basic of beats. A standard lineup included a lead and a bass voice paired with two or three utility voices providing harmony and rhythm with joyously unapologetic gibberish. The stuff was irresistibly catchy and, in the case of the Chips' "Rubber Biscuit," downright hilarious. The Clovers and the Five Keys approached the form with a bit more sophistication, employing jazzy compositions and highly specialized singing. Harder-edged, R&B-based bands such as the Cadillacs and the Robins paved the way for the Doo-Wop-heavy, early rock 'n' roll sound of the Coasters.