How can I put the categories on the cover

How can I put the categories on the cover, to appear in this way? there is a way. I put an example image
If you look at pages/category.inc.php half the job is done. You just need to create an iterator that loops through all subcategories.
Thanks, I have no knowledge on how to do it, thanks for answering.
If you look at the view at includes/templates/default.catalog/pages/category.inc.php you can see how one category is output. Imagine you had an array foreach loop.

The following files have code you can copy and build upon.

pages/categories.inc.php
pages/categoriy.inc.php
includes/templates/default.catalog/pages/categories.inc.php
includes/templates/default.catalog/pages/category.inc.php

The problem with this idea is what's gonna happen with a 2nd level subcategory?