# File karel/tk_robot_world.rb, line 24
  def initialize (name)
    super()
    # puts 'new tk robot world'
    @name = name
    @beepers = Hash.new(0)
    @east_west_walls = Hash.new(0)
    @north_south_walls = Hash.new(0)
    @robots = Hash.new(nil)

    @beepers.extend(MonitorMixin)
    @@beeper_control = @beepers.new_cond
   end