% road(X,Y): city X is connected to city Y by a road
road(durango,redville).
road(redville,durango).
road(redville,hardwick).
road(hardwick,redville).
road(hardwick,newton).
road(newton,hardwick).
road(newton,burr).
road(burr,newton).
road(newton,hallsburg).
road(hallsburg,newton).
road(newton,burlington).
road(burlington,newton).
road(hallsburg,burlington).
road(burlington,hallsburg).