Matrix in Matrix Workaround

matrix-collection.twig

{% macro outputTiles(tileList) %}
    {# use macro to keep it DRY #}
    <div class="tiles">
    {% for tile in tileList %}
        <div class="tile">{{ tile.tileTitle }}</div>
    {% endfor %}
    </div>
{% endmacro %}

{% if entry.testMatrix is defined %}
    {# start with empty array #}
    {% set tileList = [] %}

    {# loop through matrix blocks like normal #}

    {% for block in entry.testMatrix %}

        {% if block.type != "tile" and tileList|length %}
            {# here's where we actually output the tile group #}
            {{ _self.outputTiles(tileList) }}

            {# once we've outputted the tiles, empty the list #}
            {% set tileList = [] %}

        {% endif %}

        {# normal switch on block.type #}
        {% switch block.type %}

            {% case "textBlock" %}
                <div class="textBlock">Text Block</div>

            {% case "imageBlock" %}
                <div class="imageBlock">Image Block</div>

            {% case "callToAction" %}
                <div class="callToAction">Call to Action</div>

            {% case "tile" %}
                {# instead of outputting anything, we save this tile to our list for later outputting #}
                {% set tileList = tileList|merge([block]) %}

        {% endswitch %}
    {% endfor %}

    {# once we've finished the loop, we output any tiles that were at the end of the loop #}
    {% if tileList|length %}
        {{ _self.outputTiles(tileList) }}
        {% set tileList = [] %}
    {% endif %}

{% endif %}
{# that's it! #}