Syntax: A single line

A verbatim line.

Syntax: A single line with leading spaces

  Another verbatim line, with leading spaces.

Syntax: Area (block)

A verbatim area delimited
       by lines with marks.

Syntax: Area (block) with trailing spaces

Trailing spaces and TABs after the area marks
are allowed, but not encouraged nor documented.

Invalid: No space between mark and contents

```Not a verbatim line, need one space after mark.

Invalid: Leading spaces on block marks

``` Not a verbatim area. The marks must be at the line beginning, no leading spaces. ```

Closing: EOF closes the open block

The end of the file (EOF) closes
the currently open verbatim area.