A good answer might be:

Poems, math formulae, columns of numbers, example program output. But sometimes it is better to use HTML tables for some of these. See this topic in a later section.

Practice with Pre

Here is a Web page with a program that should be pre-formatted:

See what happens to the poor program as it is. Then insert some <pre> ...</pre> tags so that it keeps its formatting, and click to see what the HTML does.

QUESTION 20:

It is often nice to indent preformatted text. The combination: 

<blockquote><pre>

Indented, preformatted, text

</pre></blockquote>
Is useful for this. Use it with the above program to see its effect.