Early 20th-century movements rapidly redefined art while pop styles kept changing

Evidence

Compare this to the explosion of cultural invention during the first twenty-five years of the twentieth century: Avant-garde movements such as fauvism, cubism, futurism, expressionism, Dada, de Stijl, and surrealism expanded the definition of art. Later in the century, stylistic change remained a core part of pop music: Punk supplanted prog rock, rap buried funk, and alternative conquered hair metal and synth pop. And all these radical forms possessed enough depth to still inspire us today. — W. David Marx, Blank Space, 16

Categorization

• XREF: The reader’s four-period structure trace needs this baseline of past cultural dynamism to contrast against the blank space.