American Scientist

I have long worked at a desk stacked with towers of books and papers. Whenever I returned from an extended absence, I could also expect to find a large pile of mail. On one occasion, it reminded me of a tower about to topple over, its instability coming from a curiously bulky envelope on which all the smaller and flatter ones rested. Reaching inside the puffy package, I felt something soft, which turned out to be a blue T-shirt bearing the slogan “The Upright Towers of Pisa,” printed above a photo of an Italian skyline punctuated by perfectly vertical towers.