Being a mathematician with mathematician friends, my friends and I occasionally like to joke about the peculiarities of the English language. This one came up recently:
Obviously, most English sentences and phrases cannot be read backwards and forwards and maintain the same meaning. For instance, "watch this" and "this watch" have clearly different meanings. In mathematics, we call this non-commutativity, and it is deeply interesting. So the question is, can anyone think of a phrase or sentence which has the same semantic meaning when the words are read from right to left?