The fireplace has lights, which require electrical power. There are a couple ways to transmit power through a rotating joint, like the pivot around which the fireplace turns. The first is to use a slip ring. This is something like your headphone jack. It has wipers that allow electrical signal transmission even when the center is rotated infinitely. The trouble with slip rings is that ones rated for transmitting any significant power are expensive. (They also eventually wear out.) The cheap way is just to run cables up through the joint. With this method, the number of turns is limited before you need to reverse and untwist the cables.
If you notice, on the side of the stage opposite the food, there is a control station for the fireplace. During shows, an operator runs the fireplace. This station also has a video monitor displaying the picture from a camera hanging directly above the fireplace, looking down. For a unique view of the show, you can sit by the operator and watch the show from above. I've got a video clip at home I can post later. After the show, the operator runs the fireplace backward the right number of turns to untwist the cables that power the fireplace lights and fire effect.
