A couple years ago I got my first LEGO RoboLab set. I had never thought about adding gearing to my buildings, but wanted to try it, and so the Watermill was born.
It took me months to get the wheel itself built. I used MLCAD to try out different combinations of parts, and then once I was satisfied, I ordered the parts I needed. From there I built the rest of the mill and landscape, making them proportional to the wheel itself.
For the last TexLUG meeting, I added an additional landscape section to be able to encorporate the mill with my village layout.