<br/>
 Definition of a foldable part of the document
(may be folded in or out at will by the reader):
up to 3 arguments. <ul>
 <li>Argument 1: either the name of another block of the same document, or
 empty.
 </li><li>Argument 2: a text identifying the foldable part. If argument 1 is
 another block, this argument can be empty (in this case the text will
 default to the title of the cited block).
 </li><li>Argument 3: only used when argument 1 is empty, giving the content of
 the foldable part (when it is folded in). Otherwise the content of the 
 folded-in part will be that of the cited block.
</li></ul>

This very part of the page is an example of <span class="tt wims_code_words">\\fold</span>,
whose command is <span class="tt wims_code_words">\\fold{fold}{&lt;tt>\\\\fold&lt;/tt>}</span>.

For an example of foldable part within a same block, the following

<span class="tt wims_code_words">\\fold{}{Title of the part.}{Content of the part once folded in.}</span>

gives
\fold{}{Title of the part.}{Content of the part once folded in.}

<span class="wims_warning">Attention</span>. The foldable parts within a same block do not allow
automatic formatting of mathematical formulas, nor execution of 
commands.
<p>