Aspects of the present disclosure are directed to apparatuses and methods involving an engine and/or motor having piston lobes that rotate with a drive shaft or shafts, which may be implemented with a toroidal-based engine housing. As may be implemented with some embodiments, an apparatus includes drive shafts having a common axis of rotation, with each drive shaft operable to rotate independently of the other drive shaft. The housing extends around the drive shafts, and defines a sidewall of a chamber having inlet and exhaust ports. Clutch bearings limit rotation of the drive shafts to a common rotational direction. One or more piston lobes are connected to each drive shaft, with each piston lobe being disposed within the chamber and operable to move circumferentially within the chamber about the axis of rotation, with the drive shaft to which it is coupled.