Google is constantly testing variations and new ad formats for the Google AdSense ads.
The latest one was spotted by @amitsurti who shared with me a few pictures of this new ad format. The new ad format contains multiples of those circle based AdSense arrows. So each ad within the ad unit has an arrow next to it in blue.
Here are a couple of pictures of it in action:
Here is another one:
I personally cannot replicate it but Amit is definitely seeing it on multiple sites.
Forum discussion at Twitter.