A: One of us speaks only the truth
B: And I speak only lies
A: Wait, you messed that up
B: But I thought I'm supposed to be the liar?
A: That's now how--
B: Actually, you messed it up
A: Hold on, let's just start over
one of us only tells the truth
one only lies
(they are both lying: neither of them is wholly truthful nor wholly untruthful, but they are both always deceitful. it is not a riddle, it is a trap)
