One day the King decided that he would force all his subjects to tell
the truth. A gallows was erected in front of the city gates. A herald
announced, "Whoever would enter the city must first answer the truth to
a question which will be put to him." Nasrudin was first in line. The
captain of the guard asked him, "Where are you going? Tell the truth
-- the alternative is death by hanging." "I am going," said Nasrudin,
"to be hanged on that gallows." "I don't believe you." "Very well, if
I have told a lie, then hang me!" "But that would make it the truth!"
"Exactly," said Nasrudin, "your truth."