A month ago we caught Google testing a somewhat awkward layout for showing the AMP icon without the AMP text next to it. Shortly after that Google tested the AMP logo in blue with the word Instant next to it.
Google is back at testing a single AMP logo or icon, but the user interface and layout is less awkward this time. Here is a screen shot from Glenn Gabe on Twitter:
Glenn posted more screen shots on Twitter but this look seems better to me than the previous one.
I doubt people know what AMP means, which is why they tested "Instant" and which is why the lightening bolt icon is better than writing AMP next to it.
Forum discussion at Twitter.