The main purpose of our software is to visualise the classical results in differential geometry on PC screens, plotters, printers or any other postscript device, but it also has extensions to physics, chemistry, crystallography and the engineering sciences. To the best of our knowledge, no other comparable, comprehensive software of this kind is available.
The software is open which means that its source files are accessible to the users, thus enabling them to apply it in the solutions of their own problems. This makes it extendable and flexible, and applicable to both teaching and research in many fields. The software uses OOP, object oriented programming, and its programming language is PASCAL. The software is self-contained in the sense that no graphics package is needed other than PASCAL.
The advantages of PASCAL are the hierarchy of objects and the polymorphy which is not available in some OOP languages. In the hierarchy of objects, a successor inherits all the data, in particular the methods and procedures, of its predecessors. Polymorphy means that virtual methods can be declared in an object, a virtual method can be rewritten with the same name in a successor of the original object, and one may have more methods than one with the same name. The development of our software would not have been possible without OOP.