def urbanmain() = {

  import M4._

  val b_init = Board(Set(King(2,Wht,(4,1)), King(1,Red,(5,8)),

                         Pawn(4,Wht,(1,1)), Pawn(4,Red,(1,8)),

                  	 Pawn(3,Wht,(2,1)), Pawn(2,Red,(2,8)),

                      	 Pawn(2,Wht,(3,1)), Pawn(3,Red,(3,8)),

              		 Pawn(1,Wht,(5,1)), Pawn(1,Red,(4,8)),

               		 Pawn(4,Wht,(6,1)), Pawn(3,Red,(6,8)),

               		 Pawn(3,Wht,(7,1)), Pawn(1,Red,(7,8)),

               		 Pawn(2,Wht,(8,1)), Pawn(3,Red,(8,8))))

  val b2 = Board(Set(King(2, Red, (4,2)), King(2, Wht, (7,1)),

                     Pawn(3, Red, (6,1)), Pawn(2, Wht, (8,4)),

                     Pawn(4, Red, (4,4)), Pawn(2, Wht, (4,1)),

                     Pawn(4, Red, (5,3)), Pawn(3, Wht, (8,7)),

                     Pawn(3, Red, (6,5))))

  assert(attacked(Red, b2) == Set(Pawn(2,Wht,(8,4)), King(2,Wht,(7,1))))

  assert(attacked(Wht, b2) == Set(Pawn(3,Red,(6,1))))

  assert(attacked(Wht, b_init) == Set())

  assert(attacked(Red, b_init) == Set())

}