Looking to replace a water feature in the garden, my parents came back with a working waterwheel.
Powered by a couple of solar cells, it's not little thing. The base is 46cm square and it's 54cm tall.
I wondered how close it is to 16mm scale, and the answer, is: a bit small.
Unpainted Tag is just over 10cm tall, a big bigger than the real thing if we are being picky about scale, but you can see he towers over the "door". Although it looks like a window, but that's the least of the problems.
That said, the thing works well, and for £130, isn't stupidly expensive compared to other resin buildings. Used towards the back of a layout, it could be said to impart useful forced perspective. If you like cartoony buildings in the garden, it fits in well to the scene.
Water is pumped from the reservoir at the base, and needs a fair bit of sun to make things works. When they do, the direction the wheel revolves (it's driven by the water) seems to be pot luck.
Pleasingly, for tinkerers, there is a hatch in the back so you can get at the pump. If it fails, look out for a blog on replacing it.