# File sparklines.rb, line 435
        def self.plot_error(options={})
                img = Magick::Image.new(40,15) {self.background_color = options[:background_color]}
                img.format = "PNG"
                draw = Magick::Draw.new
                draw.fill('red')
                draw.line(0,0,40,15)
                draw.line(0,15,40,0)
                draw.draw(img)

                img.to_blob
        end