A guy-wire or guy-rope is a tensioned cable designed to add stability to structures (frequently ship masts, radio masts, wind turbines, utility poles, and tents). One end of the cable is attached to the structure, and the other is anchored to the ground at a distance from the structure's base. They are often configured radially (equally spaced about the structure) in trios, quads (pairs of pairs) or other sets. This allows the tension of each guy-wire to offset the others. For example, roof antennas are sometimes held up by three guy-wires.