Bicycles are not used only for making exercise or allowing us to move from point A to point B. Bikes have been considered and even today are considered as tools for working. One example is the photo bellow. It was a bike-sharpener, so that the professional who rode it only needed his legs to both sharpen knifes and scissors, and travel from village to village. I found this history jewel in a museum as such interesting machines should be preserved.