Answer: it comes from the famous persian tale ‘Ali Baba and the 40 thiefs’ (Ali Baba ve kirk haramiler, in turkish). It is the story of a young man who discovers a cave, where 4o thiefs have hidden away all their robberies. The cave though can only be opened by saying ‘open sesame’. One day, Ali Baba, after having heard the password, enters the cave and takes with him whatever he can take. When the thiefs come back, there is nothing in the cave anymore. The thiefs discover after a certain time, where Ali Baba lives and go to his town and house. The thief in chief pretends he’s travelling, while he has hidden away in the jars, the other 39 thiefs. Ali Baba discovers that it is a trap and pours burning oil on the jars and all the thiefs die.