The king of Persia has a visitor who will be his new minister of defence. When he comes the king greets him and asks politely “would you like a tour of the city ” the visitor says “ok“.

As the two of them are walking the king points at a beggar with a donkey and says “that man there is the richest man in the city apart from me” the visitor asks “how“the king replies “well he seems to be smuggling something, but we don’t  know when he does it ” so the minister comes up with an idea of having guards search him whenever he goes in or out of the city but this plan does not work.

What does the man smuggle?