Snow grooming is the process of manipulating snow for recreational uses with a tractor, snowmobile, piste caterpillar, truck or snowcat towing specialized equipment. The process is used to maintain ski hills, cross-country ski trails and snowmobile trails by grooming (moving, flattening, rototilling, or compacting) the snow on them. A snow groomer is usually employed to pack snow and improve skiing and snowboarding and snowmobile trail conditions. The resulting pattern on the snow is known as corduroy, and is widely regarded as a good surface on which to ski or ride. Snow groomers can also move accumulated snow made by snow machines as part of a process, called "snow farming".