Like lace, plaid spoke many languages this fall. There were big, bold lumberjacky patterns at Y-3 and collegiate-sporty-preppy mixes at rag & bone and Burberry, whose natural showplace would seem to be a football game on a chilly afternoon, or maybe a stylish tree-chopping party. Other plaids have a more serious, indoor vibe, like the dark patterns at Louis Vuitton and Yves Saint Laurent, which very clearly say, "I'm going to work. Please do not mess with me."