# File karel/karel_window.rb, line 287
  def make_boundary_walls
    x, y = scale_to_pixels(0.5, 0.5)
    @_walls << TkcLine.new(@canvas, x, 0, x, y, :width => 2)
    @_walls << TkcLine.new(@canvas, x, y, @_right + $inset, y, :width => 2)
  end