The publishers are WebmasterWorld are noticing Google AdSense testing lots of flavors of AdSense ad arrows.
Personally, I was able to see square boxed in arrows, rounded edged boxed in arrows, no arrows at all and even a rectangular boxed in arrow.
Here are some screen shots of the various AdSense arrow tests Google is testing:
Have you seen others being tested recently by Google?
Forum discussion at WebmasterWorld.
