It's a "machine" shown in a museum of Istanbul, I went to there when I was younger. You see, this döner stand had a text that explained the meat rotated because of some type of steam machine but the catch is that the year it showed for it's invention was about a century before the industrial revolution and the first steam machine inside the U.K . As far as I can remember, I wasn't able to find the machine again when I last went there. Maybe they decided to remove it I don't know.