So Pythagoras walks into a bar. He walks up to the bartender, and starts complaining, "So I've got this problem. I had a hunch that if you take two 9:8 tones away from a 4:3 fourth, you actually don't end up with half a tone. So I did all the math - took the two tones from the fourth - and added the remainder to itself to get the result, and indeed, it's not a tone. So I don't even have any idea what to call that result."
"Gee, I dunno," says the bartender, rolling his eyes mock-sympathetically. "Sounds like you've got a real di-lemma."