All of which is to say that his show, which was also the last of New York Fashion Week, was a lot more than just a show. It was a litmus test: of his continued relevance, which is deeply intertwined with New York’s relevance, and of his intentions.

So what color did the strip turn?

Every color of the rainbow. In a silent show held in the cavernous environs of the Park Avenue Armory, with the audience arrayed at the far edges of the space, the empty wood floor so vast that the people sitting across the way looked like little ants on their folding chairs, out came a stream of ideas and images, churned up and recombined, vivid and oversize.

It was not a breakthrough; many of the pieces referred to collections Mr. Jacobs had done before, which he acknowledged in his program notes, writing that the show was “the reimagining of seasons past somewhere beyond the urban landscape of New York City.” But it was a convincing staking of territory, a pointed reminder of exactly why this designer matters.