White Cement Mixer Truck in a Work Yard

Inside the drum of a cement mixer truck runs a spiral blade, like the thread of a screw. Turned one way, it keeps the concrete churning and pulls it deeper into the drum on the drive to the site. Reversed, the same spiral pushes the load up and out through the chute. A white one waits in a muddy work yard in this cement mixer jigsaw puzzle, its drum splashed gray from the last pour.