If you're talking about the one that's on for today 30 December, with the smaller container inside and at the top of the larger drum:
Apparently the load is placed in the smaller container, which is sealed; and then the washing action is performed by sliding that container up and down repeatedly into the wash water in the larger drum below it, forcing the water through the smaller container. The whole thing is sealed up when in motion.
Kinda' clever, but should probably be bolted down to a serious concrete slab, otherwise I think it would tend to hop all over the place with much noise.
