When you picture hippies, you probably think of bell bottoms, long hair, and LSD. You might also think of a very specific graphic design and illustration style, seen on concert posters and album covers: curly, cloudy, barely legible lettering; trippy color combinations; and decorative meandering borders.

This style was first conceived in San Francisco by a handful of designers in the late 1960s. Their job? Make posters for bands like The Byrds, the Grateful Dead, Janis Joplin, Steve Miller Band, Jimi Hendrix — all of whom were just getting their start, competing for nightly stage time at venues like the Fillmore and the Avalon.

But these designers didn’t invent that now-iconic style. In fact, they were heavily influenced by an art movement that started in the late 1800s called Art Nouveau.

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