You can read all the comics here [link]
Okay, not so much a "circle" as a "food chain". Norwegians and Swedes think their beer is too expensive and cross the water to buy it in Denmark (or Finland, but we don't talk about that). Danes just think beer is too expensive in Scandinavia as a whole and cross the border to buy it in Germany. And Germans buy their beer in...nah, I could go on forever.
Yup, they're singing drinking songs. The first is a Swedish drinking song that is sung all over Scandinavia. The second is of course German.