The RepRap project was how I first learned about 3d printing. It has the remarkable mission, in that I’m remarking about it, of printing all of the parts to make another printer. Wow. Well, in principle, all of the circuits can be replaced with pneumatic ones. And also, you know, it might make a cool theme for a sci-fi flick. Just imagine a 3d printer printing with a background of hydraulic valves, pumps and hoses. Generate a pressure difference with steam and you’ve made a steam punk wet dream.