[Haskell-beginners] recommendations for a gnuplot tutorial

I've looked for a tutorial for using the Haskell gnuplot wrapper, and can't find anything. If you can think of one off the top of your head, please let me know. I'd like to see how to use it to generate 2D and 3D histograms expressed in a png (or any) file. As far as I can see, the examples that come with gnuplot don't generate files.