# File karel/karel_window.rb, line 276
  def make_streets_and_avenues
    @_streets.times do |i|
      x,y = scale_to_pixels(i + 1, 0.5)
      tx,ty = scale_to_pixels(i + 1, @_streets + 0.5)
      @_walls << TkcLine.new(@canvas,x,y,tx,ty, :fill => 'red')
      x, y = scale_to_pixels(0.5, i + 1)
      tx, ty = scale_to_pixels(@_streets + 0.5, i + 1)
      @_walls << TkcLine.new(@canvas,x,y,tx,ty, :fill => 'red')
    end
  end