Revealing the fashion fixations of Dallas’ top trendsetters is our obsession here at DFW Style Daily. Today, haute blogger Heather Lettieri gets graphic, sharing her stylish, geometric addiction exclusively with us.   Known for her DIY-meets-designer tastes, Lettieri is the author of Against the Grain. (To wit, her award-winning seaside ensemble at Mockingbird Station’s What To Wear event last month included a hand-appliquéd clutch.) The 23-year-old is a staple on the city’s fashion scene, and we always appreciate her risk-taking approach to style. Below, we’ll learn which iconic, artist-inspired pieces she’s collecting this season.     The Obsession: All Mondrian, all the time.   The Confession: “I imagine my obsession was sparked by my palpable excitement for the opening of the new YSL boutique in Highland Park Village,” Lettieri explains. “The five game-changing, geometric dresses Yves Saint Laurent designed in 1965 as an homage to Dutch artist Piet Mondrian are legendary.”           The Rationalization: Musing on why Mondrian-inspired pieces are a cut above other graphic prints, Lettieri notes, “I lust for color, and I think this is a much more artistic and, when presented correctly, potentially elegant way of livening up the color blocking trend.”               The Collection: “There are countless knockoffs - I like to call them tributes - to the ultimate YSL tribute piece,” observes our stylish subject. “However, I'm loving the print on everything, including new twists on the iconic dress, shoes, jewels, even manicures and home accents!”               Shop It: Lettieri proclaims swimwear to be “the hottest way to rock this style.” Here, we feature a look by Sarah Schofield. Additional picks, shown above, include Kate Spade’s necklace and home décor items from The Courtauld Gallery in London.               (Photo Credits, from top: 1. Elliot Munoz, 2. AtMuscleBeach.Blogspot.com, 3. Endless.com, LiveAuctioneers.com, Polyvore, CultureLabel.com, 4. Flickr)