Event Storming is is a way to abstract the key events in a system, and is often used with Domain-driven design (DDD).
In this example we have the events of the somewhat less than happy case where a car owner has decided to fight a traffic ticket and needs to take a personal day to attend traffic court.
The following web page gives a nice introduction:
http://webeventstorming.com/
Their tool (which I beta-tested to a small degree, and was used to produce the above diagram) does a nice job of compressing white space as necessary while respecting places where it is needed for readability.
Please refer to the SEDA folder for information on SEDA (Staged Event-Driven Architecture).