A collection of demonstrations ranging from the very simple (Hello World), through the practical (TinySine & Rose demonstrate simple uses of the module LibPlotters) to the sophisticated.
Donald Knuth has a very flexible (abstract) problem solving algorithm, called "Dancing Links" or "DLX". This is implemented with examples that include an efficient Sudoku solver and a Polyomino placement solver.
The use of "Turtle graphics" (called Gerbil graphics here!) to create recursively designed curves, such as Dragon curves is also demonstrated.
The most sophisticated example is a mapping tool, with many options, that can download worldwide maps in many formats such as Open Street Map or Open Cycle Map, and manage Tracks and Routes in gpx format compatible with many external GPS devices.