PlantUML macros and other includes for Event Modelling
PlantUML is an open source project that allows you to create UML diagrams. Diagrams are defined using a simple and intuitive plain text language. It uses Graphviz software to lay out its diagrams. Images can be generated in PNG, in SVG or in LaTeX format.
Event Modeling is a method of describing systems using an example of how information has changed within them over time.
Here is a good place to understand how it works.