def urbanmain() = {
  import M4._

  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(protectedN(Pawn(2, Wht, (8,4)), b2) == 1)
  assert(protectedN(Pawn(4, Red, (5,3)), b2) == 3)

}