Matthew Williamson is on his own trip. Season in and season out, he practices a particular brand of Ibiza chic: neons, bohemian beading, and caftans are always in his bag of tricks. With bright colors and bold prints on the checklist for retailers (these items' cheery optimism makes them reliable sellers in a depressed economy), Williamson is in step for Spring. Sequined racerback tank maxi dresses in a graphic print jersey will make the cut with stores and longtime fans like Julia Stiles and Joy Bryant, the latter of whom sported one of the designer's sundresses with sandals, despite an impending downpourhow's that for optimism? Also in the plus category: a belted, allover sequin tunic dress; a beaded bed jacket worn with an easy T-shirt and cropped white jeans; and an absolutely electric abstract floral-print chiffon that was used for a very of-the-moment jumpsuit, as well as parachute pants and one of Williamson's signature caftans. He veered too far off course, however, with a black leather bustier and motocross pants. Why mess with a good thing?