A spreadsheet-like visual modelling tool
WING (a WINdowing and Graphics tool) was originally conceived as the implementation of a definitive notation for windowing and graphical objects. However, during its development, the focus of attention shifted to its capabilities as a full EM tool. WING provides 15 data types in four categories, namely basic, windowing, graphics and vector data types. The modeller can also define new data types and operators. For more details, the reader is directed to Allan Wong's thesis, Before and Beyond Systems: An Empirical Modelling Approach.