This is a wonderful and fascinating still life by Juan Sanchez Cotan: http://www.friendsofart.net/static/images/art1/juan-sanchez-cotan-still-life-with-quince-cabbage-melon-and-cucumber.jpg

It is thought by many art historians that the artist used a mathematical formula to determine the heights at which the various items would appear. For all I know this may be the case, but I once read part of a book by a very respectable art historian (whose name I have maddeningly forgotten but I'm working on it) who said what the formula was. His evidence was just the picture itself and not any surviving record of how it was painted. But of course, given that the heights of the items are not precisely determined (anything like), it is clear that any number of curves could be declared to fit. This is not exactly misuse of a theorem but it was certainly misuse of mathematics, similar to finding the golden ratio everywhere but a bit more sophisticated.