Itsy bitsy spider

Petri nets are used to represent asynchrones parallel running processes; the implementation varies from dialect to dialect like the high-level petri net or the hierarchical petri net. The most common dialect today is the colored petri net.

Places and transition

Places are used to represent a state along the net. These places can hold tokens. A place is denoted by a hollow circle and a token is a filled in circle. Places hold token until they get piped into another place by a transition.

Transitions behave like functions; they take a toke input parameter from one place and map them into a token in another place, consuming the token in the process. They are represented by a black bar which get connected by edges between 2 or more nodes.

Example