This document is written in Markdown.
See the documentation on Markdown compatibility.
Images
Any kind of image can be used.

Arbitrary HTML
All HTML code is valid in Markdown, such as a <video> tag:
Embedding content
Numbas
A Numbas exam can be embedded into a document with the <numbas-embed> tag:
oEmbed
Chirun supports embedding content from any page that supports the oEmbed protocol, such as YouTube.
Code blocks
Some static Python code:
print("Hello", "World")
Some Python code that can be evaluated:
Output from a program:
usage: git [--version] [--help] [-C <path>] [-c <name>=<value>]
[--exec-path[=<path>]] [--html-path] [--man-path] [--info-path]
[-p | --paginate | -P | --no-pager] [--no-replace-objects] [--bare]
[--git-dir=<path>] [--work-tree=<path>] [--namespace=<name>]
[--super-prefix=<path>] [--config-env=<name>=<envvar>]
<command> [<args>]