Automated test equipment have traditionally generated a two-dimensional, ASCII form of the shmoo plot that uses an "X" to represent functional points and blank space for non-functional points. In modern times plots with two colors (e.g. red/green) or even multi colored plots in form of digital spread sheet documents and alike became also common, even if the traditional form is still in use. For testing efficiency sometimes only the border of interest (where a certain value changes its state) is backed up with data in the diagrams thus (often reasonably) assuming the areas outside those transition will stay at those state.