… Were traveling through Romania when they saw a black cat through the window of their bus:
“Aha!”, says the engineer, “I see that Romanian cats are black”.
“Hmm!!”, says the physicist, “You mean that some Romanian cats are black”
“No!!!”, says the mathematician, “All we know is that there is at least one cat in Romania, and that at least one side of that one cat is black!” 😉 …