Beyond wondering if they're clashing, you probably don't give much thought to the patterns you're wearing. But did you know that your polka-dot blouse is the same print that a group of dancers in the '60s chose to protest Wall Street funding for the Vietnam War? Or that plaid first became cool (instead of just there) when it was banned in 18th-century England? Stories like these fill the pages of Jude Stewart’s Patternalia: An Unconventional History of Polka Dots, Stripes, Plaid, Camouflage, & Other Graphic Patterns — a new book about the many patterns we encounter every day, but probably know little about. Blending history, culture, fashion, fairy tales, math, and science, Stewart shows how patterns aren't only designs, but also symbols packed with politics.Stewart — who likes to wear stripes, but also has a penchant for black-and-white checkerboard — found that prints are actually an effective tool for political mobilization: “Patterns help unify a group, and they also help you know who’s in [it] and who’s out.” What does it say when a person wears patterns for political reasons? “It says they probably want to have a conversation about politics, or maybe a fight. It’s sort of like wearing a button that says, ‘Ask me about abortion rights,’” she says. “If you’re gonna wear a pattern that has political resonance, just be ready for the conversation you’re going to start by wearing it.”