Need help with asides

Hello all

I’ve added asides to my blog (https://www.bildredakteur.net) using the code found here to show posts in a special category. It works great. That’s how the code looks at the moment:

<ul>
<?php rewind_posts(); ?>
<?php if ($posts) : foreach ($posts as $post) : start_wp();
?>

What I now would like to do is limit the asides to the last 2 posts. Tried to do it with a for-loop, but it doesn’t work. Has somebody an idea how to fix this?

Many thanks
Alain