I'd say they're Jabos. They aren't single fold though, but not all jabos are. I don't know what else they would be though.
Imagine glass coming out of a little hole in a tank of molten glass. It will come out in a thick stream. Like toothpaste coming out of a tube, pointing down and hanging. This is what the marble is made of. If it's a big stream, it can't be long before there is too much glass to make a marble so the cutter is set to cut the glass more quickly. If it's a thin stream, it has to run a while to pile up enough glass to make a marble so the stream drizzles a longer while before the cutter cuts it. Imagine getting enough to make a marble through a drinking straw, then imagine getting enough through a syringe. This pile it would take before you get enough to make a marble, that is your swirl pattern. It might loop around over and over in the same direction and make a flame like some alleys. It might flip, curl, loop back, cut across and make a random pattern like most swirls, or if it's a large stream, it might only flop over on itself in a "U" shape like jabo classics do. If the stream is large enough across (comes out of a really large hole in the tank), it won't loop at all, it will be a patch style. Then it goes onto the rollers and they make it round and cool it down as it gets to the end of the rollers.