A wag met Nasrudin. In his pocket he had an egg. ‘Tell
me, Mulla; are you any good at guessing games?’
   ‘Not bad,’ said Nasrudin.
   ‘Very well, then: tell me what I have in my pocket.’
   ‘Give me a clue, then.’
   ‘It is shaped like an egg, it is yellow and white inside, 
and it looks like an egg.’
   ‘Some sort of cake,’ said Nasrudin.