<div class="d-flex flex-wrap align-content-stretch">
<div class="p-2">Flex item</div>
<div class="p-2">Flex item</div>
<div class="p-2">Flex item</div>
...
</div>
<!-- responsive variations -->
<div class="d-flex align-content-sm-stretch">...</div>
<div class="d-flex align-content-md-stretch">...</div>
<div class="d-flex align-content-lg-stretch">...</div>
<div class="d-flex align-content-xl-stretch">...</div>