Mermaid diagrams

A fenced code block marked mermaid renders as a diagram. A flowchart:

flowchart LR
  A[Idea] --> B(Draft)
  B --> C{Review}
  C --> D[Publish]
  C --> B

The same syntax draws every diagram type Mermaid supports. A sequence diagram:

sequenceDiagram
  participant Author
  participant Editor
  Author->>Editor: Submit draft
  Editor-->>Author: Request changes
  Author->>Editor: Submit revision
  Editor->>Author: Accept

Ordinary code blocks are unaffected:

print("hello")