static void Main(string[] args) { HashSet <Terrain> t1 = new HashSet <Terrain>() { new Forest(), new Steppe() }; HashSet <Terrain> t2 = new HashSet <Terrain>() { new Forest(), new Water() }; HashSet <Terrain> t3 = new HashSet <Terrain>() { new Water(), new Steppe() }; HashSet <Terrain> t4 = new HashSet <Terrain>() { new Forest(), new Steppe(), new Water() }; List <Cage> cages = new List <Cage>() { new Cage(t1), new Cage(t2), new Cage(t3), new Cage(t4) }; Keeper keepkeep = new Keeper(); Console.WriteLine(keepkeep.AddAnimal(cages, new Boar())); Console.In.ReadLine(); }