I was at the Museum of the American Revolution and I saw an image repeatedly that I had never seen before that appeared on currency and other artifacts. It was thirteen rings, each ring had a colony's name on it, linked together in a circle. In the center there was a "US" ring (or something to that effect). Any help identifying this symbol? I think I heard someone call it the "ring of states" or "chain of states" but google is not helping me find anything! Thanks in advance!