Making a good poster is hard, but most people wouldn't considering it harder than creating a robot to make the poster for you. Not so for Wyatt Felt, a member of instructables, who created a robot out of not much more than an iRobot Create, an old inkjet, and a sharpie which, put together, can draw perfectly spaced large lettering. Like an inkjet, it's made of individual pixels: but the PosterBot's pixels are the size of a dab of a large sharpie, so the poster is easily readable from a distance. If you want to create a PosterBot yourself, you'll have to have a fair degree of competency with C++, and a whole lot of peripheral kit to build the thing. You make sure to keep at least four PC-Mount DPDT 5v DC relays rated at 1A lying around, don't you?