Who Wears This Stuff

On New York City runways last week, designers showed off their hippest new fashions, from tight miniskirts to billowing pantaloons, like the ones, left, from Marc Jacobs. It's just a matter of time before these looks trickle down to the early adopters, then to the mass market. Here's a play-by-play of how fashion happens, focusing on the leggings craze that was so hot last year (before those pantaloons). LONDON CALLING The leggings look resurfaced last fall when people like Kate Moss were spotted wearing them in London.

RUNWAY PROJECT New York trendsetters like designer Derek Lam borrowed the look and kicked it up a notch with an edgy '80s homage.

STAR TREATMENT Leggings moved further along the fashion food chain when celebs like Jessica Alba made the look their own.

COME AND GET 'EM By late August, Gap was featuring leggings under distressed denim miniskirts in its splashy fall ad campaign.