Last night we were watching the beginning of the NHL game between Trono and Philadelphia, and I mentioned to my granddaughters that I had once played hockey. They were quite taken aback for some reason, which I am sure had nothing to do with my general lack of athleticism and my clear disinterest in the NHL these days.
So I went to the closet and dug out my old hockey jersey.
Economists may recognize the stylistic version of the Edgeworth Box Diagram. I think the designer sketched an example and then the sweater producer just used some circles to make the curves, leading to interesting negative marginal utilities. The curves on the sweater aren't necessarily incorrect, but they were not the shapes of curves we saw in standard textbooks 40 years ago. E.g.: