Vertical slides in overview scrolling in columns - how to?

[mlange-42]

Hi everyone!

In the reveal.js presentation on w3.org, I have seen behaviour of vertical slides in the overview differing from the usual one.

Slides scoll in columns rather than the usual panning of the entire view (see screenshot below). How can this be achieved? I found nothing in the settings of this deck. Or is this just an old version of reveal.js (presentation seems to be from 2013)?

And BTW... is it possible to start a stack of vertical slides somewhere else than at the top?

Thanks!