With that you can use the mermaid language in Markdown code blocks:
mermaid
1```mermaid2sequenceDiagram3 participant Alice4 participant Bob5 Alice->>John: Hello John, how are you?6 loop Healthcheck7 John->>John: Fight against hypochondria8 end9 Note right of John: Rational thoughts <br/>prevail!10 John-->>Alice: Great!11 John->>Bob: How about you?12 Bob-->>John: Jolly good!13```
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 prevail! John-->>Alice: Great! John->>Bob: How about you? Bob-->>John: Jolly good!
