Games of this style feature three-dimensional, polygonal graphics and gameplay that alternates between opponents. Turn-based strategy games usually involve competition, if not all-out warfare, between at least two forces. Because the game progresses incrementally and players may have unlimited time to consider each move, long-term planning based on accurate evaluation becomes important for success. Though sometimes included primarily for aesthetic concerns, 3D polygonal graphics allow for realistically varied terrain, including elevation differences that may affect reconnaissance and combat tactics.