Evenly dividing up table items in columns
It's actually quite simple! What you're looking for is Twig's batch filter... Ironically, the example given on that page is nearly identical to what you are requesting.

I've adapted the example to more closely match what you're looking for:

{% set myData = ['a', 'b', 'c', 'd', 'e', 'f', 'g'] %}

{% for column in myData|batch(3, 'No item') %}
    &lt;div class="medium-3 medium-offset-2 small-centered medium-uncentered columns"&gt;
        &lt;ul&gt;
            {% for item in column %}
                &lt;li&gt;{{ item }}&lt;/li&gt;
            {% endfor %}
        &lt;/ul&gt;
    &lt;/div&gt;
{% endfor %}