This is a fun one. It's simple yet subtle. I doubt I would have recognized that it was an ambigram if you had not pointed it out. It just looks like a fancy border!
Then I've succeeded. I wanted something that would hold more and more interest, the more you look at it. The other side, for example, has a creative series of UPC codes. One looks like a knife spreading peanut butter; another is a chef's hat; a third is milk spilling from a spoon to a cereal bowl, and so on.
Now I am curious about the other side obviously. Are you planning to share that as well?