How to list an entries selected nested categories? I have a entry field populated by categories. The number of categories an entry can have is unlimited and the categories are set up as nested categories i.e. 


first level
---second level
------third level
first level 2
---second level 2
------third level 2


I want to be able to list out any categories selected at the third level that the entry may have selected if a certain parent category is identified. So far I have the following code. This works but lists all child categories for the identified parent instead of just the selected ones.

What am I missing?

{% set cats = entry.categories %}
{% for cat in cats %}
    {% if cat.slug == 'secondlevel1' or cat.slug == 'secondlevel2' %}
        {% set catChildren = cats.descendantOf(cat.id).descendantDist('1') %}
        {% if catChildren | length %}
            {% for childCat in catChildren %}
                {% set image = childCat.buildingBlockIcon.first() %}
                    {% if image %}
                        &lt;img alt="{{ childCat.title }}" src="{{ image.url }}" /&gt;
                    {% endif %}
            {% endfor %}
        {% endif %}
    {% endif %}
{% endfor %}


----- EDIT Solution -----

I worked this out

by changing one line of code line 4 above from

{% set catChildren = cat.level(2).children %}


to

{% set catChildren = cats.descendantOf(cat.id).descendantDist('1') %}


Now works a treat. Any better solutions feel free to post.
The final solution I got to work:

{% set cats = entry.categories %}
{% for cat in cats %}
    {% if cat.slug == 'secondlevel1' or cat.slug == 'secondlevel2' %}
        {% set catChildren = cats.descendantOf(cat.id).descendantDist('1') %}
        {% if catChildren | length %}
            {% for childCat in catChildren %}
                {% set image = childCat.buildingBlockIcon.first() %}
                    {% if image %}
                        &lt;img alt="{{ childCat.title }}" src="{{ image.url }}" /&gt;
                    {% endif %}
            {% endfor %}
        {% endif %}
    {% endif %}
{% endfor %}