SPRING 2014 READY-TO-WEAR Y-3 / Yohji Yamamoto is sick of fast fashion. Or "groupie fashion," as he calls it. "They all look the same," he said in a downtown hotel lounge just hours before his Spring Y-3 show. Y-3, the designer's long-running collaboration with Adidas, is supposed to be an antidote to fast fashion's proliferation. "It's based on a sporty elegance," he said. "It can easily be mixed with pieces from my main line."