Mermaid is a tool that lets you generate flow charts, sequence diagrams, gantt charts, class diagrams and vcs graphs from a simple markup language. This allows charts and diagrams to be embedded and edited directly in the documentation source files rather than creating them as images using some external tool and checking the images into the tree.
To add a diagram, simply put something like this into your page:
.. mermaid:: graph TD; A-->B; A-->C; B-->D; C-->D;
The result will be:
.. mermaid:: sequenceDiagram participant Alice participant Bob Alice->>John: Hello John, how are you? loop Healthcheck John->>John: Fight against hypochondria end Note right of John: Rational thoughts <br/>prevail! John-->>Alice: Great! John->>Bob: How about you? Bob-->>John: Jolly good!