A couple months ago we saw Google testing a green search category navigation bubble shaped button in the mobile search results. Now I am seeing more reports of Google testing that button in other colors, like orange, gray and more. Plus, Google is also testing showing that button as a square versus oval shape.
Here is a screen shot from Juan González Villa on Twitter of the square look for this button:
Here are screen shots of the colored oval buttons from Antonio López on Twitter:
Here is the one from October when I covered it then:
This is what is currently live and not being tested:
Forum discussion at Twitter.