That's the Maggie Austin style (you could google her). She has a craftsy class where she taught it. You can see here if it's close to what you want to know. It's done with very thin fondant stripes that she ruffles by hand. She uses a pasta machine to get the thinnest stripes and also flips the cake upside down so that they keep straight. You might be able to find tutorials somewhere if you don't want to buy the class.