
generic.pl  - A generic class to perform item storage
              (exemplifies hiding of assert/retract via objects)
specific.pl - This class inherits from "generic" and extends it with
	      additional functionality
	      (exemplifies inheritance)
stack.pl    - A class that implements stacks
	      (exemplifies ADTs via classes)
multiple_inh  includes several simple examples of multiple inheritance
	      through interfaces
geometry      includes several simple examples of O'Ciao objects which are
	      associated to objects drawn in a window (via Tcl/Tk)
