[Newbies] Plotting x-y data within Squeak

My son wants to learn some programming and we would like to write some code for his science project for school. Squeak looks like a great environment in which to learn how to program, but it would be nice if he could display some of his results from his experiments within Squeak too.

Can anyone recommend a class/module/package (or whatever you call a collection of code in Squeak) that can be used for plotting graphs from a simple set of x, y values?

If not, then since I am very experienced systems programmer from the C/Lisp/Unix world I guess I'd better get my sleeves rolled up ;-)

Thanks! Andy --