Perhaps the best way to really understand the roles of these objects is through examples. Let us look at two simple tasks for modifying our storm cell application: add a menu bar and replace the Matplotlib slider widget with a similar native widget. We will do this same thing using four different GUI toolkits: GTK, Tkinter/Tcl, wxWidgets, and Qt.

A word of warning before we proceed: I am, by no means, an expert in any of these GUI toolkits. Describing me as a novice would be a stretch as well. The following examples are not intended to illustrate best practices in using the toolkits. Instead, they are intended to help inspire the readers to see the possibilities and to help get one over some of the initial hurdles that one may encounter.

Another quick note regarding our storm track application. The Tracks, RadarDisplay, and Stormcells classes have been moved out of the application into submodules; we will no longer be needing to modify these classes any...