Outsider music: classics of American classical music (29) - Wallingford Riegger - Dance Rhythms (1955) Wallingford Riegger: Dance Rhythms Op.58a (1955) Another important American composer, who was part of the first wave of modernists, alongside Cowell and Ruggles. Over time, he returned to more classical forms (like Cowell), but his significance has endured.