This is the main window. The buttons on the right perform various actions. The squares to their left with crosses in them display the individual transformations generating the image. (There are four of them in this case.) Clicking on these allows you to alter their form directly.
This is the chief subwindow brought up to edit details of how sets of transformations are randomly generated.
Yes, the interface is a little crude-looking. That's what happens when you write something in Xt using the Athena widget set. I keep meaning to update the interface to use something more modern like Tk or GTK, but then get sidetracked into adding new features instead...
If you're willing to put up with it, download this program by HTTP.