lucy24 - 11:53 pm on Feb 1, 2012 (gmt 0)

Question: If I ask you if this path is safe, what will you answer? Path A / Guard A's answer: Yes. (truthful) Path B / Guard B's answer: Yes. (liar) How could you know from that?

Your question is not "Is this path safe?" It is "What would you say if I asked?" Guard B therefore lies twice: "I would say yes" = He would really say No = The path is safe. And vice versa.

You know you're addicted to the Internet when you have a decimal-to-hexadecimal converter bookmarked, telling you that 8226 = x2022 = bullet.