A scatter plot that represents plural periodic time intervals is animated as new data points are received, where the animating includes performing real-time backward rewriting. The real-time backward rewriting includes overlaying a subset of previously written data points with the new data points, and painting a remainder of previously written data points outside the subset in the scatter plot, where painting the remainder of previously written data points is performed without shifting pixels corresponding to the remainder. A divider structure is drawn in the scatter plot to indicate a position in the scatter plot between a current time point and a previous time point.