# File karel/world_maker.rb, line 131
    def drop_item(x, y)
      canvas = $window.canvas    
      avenue, street = scale(x, y)  
      # puts street.to_s + ' ' + avenue.to_s
      if(street < 1 or avenue < 1 or street > $window.number_of_streets() or avenue > $window.number_of_streets()) 
        return
      end
      $world.place_beepers(street, avenue, 1)
    end