A coupling for coupling, for example, a trailer having a drawbar to a tractor with a three-point linkage device, which has two height-adjustable lower steering arms of which one is laterally adjustable by a lateral strut. The indicator described is optionally a flexible material, a swiveling arm integrated with an axis and a swiveling arm without an axis, a reflector or combinations of the foregoing and even multiple combinations of the foregoing to indicate various states of the container. Each of the plurality of plugs is configured to close one of the plurality of filling openings. As a user rotates the roller, the mouse generates computer signals that are interpreted by an operating system and software applications running on the computer. Using the phase error for each array, a connected phase error estimate is computed, added to the phase error of each array to minimize the differences between phases in the overlap between arrays insuring that there is no or minimal phase discontinuity in the overlap region between arrays.