Actually all baffled-piston ringed engines have multiple ports and unpinned rings which definitely rotate as the engine is running. I remember idly flicking one over and watching the ring gap very slowly moving around. The usual set up on these engines is 4 ports on the transfer side and 5 on the exhaust which is wider than the transfer side. Schneurle engines need a pinned ring because their transfer ports are quite wide although not so wide that the ring can expand into it. The much wider exhaust port though usually has a bridge in the centre for ring containment.