Riddle #670

Question: A thief enters a shop and threatens the clerk, forcing him to open the safe. The clerk says, "The code for the safe is different every day, and if you hurt me you'll never get the code". But the thief manages to guess the code on his own.

How did he do it?

Question: What do you call a sad bird?

Question: What can be broken but never forgotten?

Question: Where do all the letters sleep?

Question: People see through me, but none pass through without killing me. I can be anywhere, and can be seen double or single. What am I?

Question: What tastes better than it smells?