The eighteen thousand United Auto Workers (UAW) on strike have lit up the labor movement. But the strike is only the most visible side of autoworkers’ leverage.

The less visible side is on the shop floor, where organized refusals of voluntary overtime (OT) have shut down multiple lines and whole factories for entire weekends since the strike began.

Among the 130,000 UAW members still working at the Big Three auto companies, shop-floor creativity is bringing back a bold tradition of “work to rule” — where workers coordinate to do only their explicit duties by the book, and nothing more. When production slows to a crawl, it proves how workers’ savvy was what kept the factory humming to begin with.