Google is testing showing 3 and a half stories in the top stories carousel in search. We've seen tons of top stories user interfaces over the years and I believe I've seen this as well, but I can't find if I covered it before. So here it is.
Kyle Sutton posted these screen shots on Twitter.
Google testing 3.5 top stories in the search results:
The normal 3 card style for top stories:
Dr. Pete from Moz added to his tweet "I've seen this popping up for a few weeks (the 3-1/2 UI) -- I assume it's in testing. Seems kind of weird to me, but I guess maybe it encourages scrolling. I think side-scrolling is really common on mobile, but then no one does it on desktop, which has to be a PiTA for Google."
I like the little teaser of more stories to click on to, but that is me..
Forum discussion at Twitter.