To include a preformatted, never-to-be-fiddled-with text (e.g. a code block) finish the prior paragraph with "::". The preformatted block finishes when the text falls back to the same indentation level as a paragraph prior to the preformatted block.
An example:
Whitespace, newlines, blank lines, and all kinds of markup (like this or \this) is preserved by literal blocks. Lookie here, I've dropped the indentation level (but not far enough)
no more example
If a paragraph consists of only of "::", then it's removed from the output:
::
This is preformatted text, and the last "::" paragraph is removed
This is preformatted text, and the last "::" paragraph is removed
