Introducing HTML5 markup - HTML5 and CSS3 - page 14

<h1>Main heading</h1>
<p>Some text</p>
<section>
<h1>Level 2 heading</h1>
<p>Some more text</p>
<article>
<h1>Level 3 heading</h1>
<p>A bit more text</p>
</article>
</section>
<section>
<h1>Another level 2 heading</h1>
<p>The last bit of text</p>
</section>

We have achieved the exact same outline as the original example but
using only level-one headings. Earlier, we discussed the similarity
between <section> and <article> . If we replace one with the other in the
previous listing, you can see how similar they are:

<h1>Articles</h1>
<article>
<h1>Main heading</h1>
<p>Some text</p>
<h2>Level 2 heading</h2>
<p>Some more text</p>
<h3>Level 3 heading</h3>
<p>A bit more text</p>
<h2>Another level 2 heading</h2>
<p>The last bit of text</p>
</article>
<article>
<h1>Main heading</h1>
<p>Some text</p>
<h2>Level 2 heading</h2>
<p>Some more text</p>
<h3>Level 3 heading</h3>
<p>A bit more text</p>
<h2>Another level 2 heading</h2>
<p>The last bit of text</p>
</article>

thiS IS IDENTICAL TO THE
<section> example.
<section> AND <article> ARE
INTERCHANGEABLE FOR
OUTLINING.