With this kind of compound part you can create something that will graphically graph any data you care to give it. In-game it is used to graph chemicals but you can create your own monitoring devices - maybe a population monitor for your favourite agent?
The basis behind graphs are very simple - the engine will take care of the difficult bits for you:
You need to create a graph part on a Compound Object using PAT: GRPH. Check the format of this in the CAOS Language Guide. The only part that may not be clear is what NUMVALUES does for the graph ... this states the number of data points you will want on the horizontal axis.
You need to add lines to the graph using GRPL - a line for each set of data you wish to graph. This command allows you to specify the colour of the line and the maximum and minimum values for this line (with respect to the vertical axis)
You then need to add values to the lines using GRPV - the graph will only update after all lines have had a value added to them.
There are two simple example COS files here for download - one with only one line plotted on the graph, with a NUMVALUES of 100. The other plots three lines, with a NUMVALUES of 10. They are both plotting random points, these can be modified to plot any number you desire (both examples use -100 to +100 as the minimum and maximum values for the lines).