The cover to Joy Division's 1979 album Unknown Pleasures is as stark and enigmatic as the music itself: a series of jagged white lines against a black background that's been recreated in tattoos, clothing, and animation. In a clip for New York's Visualized Conference, former Factory Records graphic designer Peter Saville explains the origin behind the cover, which represents the frequency of the signal from the first observed pulsar or pulsating star. "As pretty much with all groups with their first release, [Joy Division] knew what they wanted on the cover," Saville says. "They gave me this page... the page from the Cambridge Encyclopedia of Astronomy." After inverting the colors, the image went on the band's first album, and into endless remixes — including the one above — during the ensuing decades.