Three-D printers are the hottest thing on the IT landscape. Everyone — users and vendors alike — wants a piece of this pie and, with many 3D systems now printing candy and food, they could get their wish; that is, an actual, edible piece of pie. 3D printers are the 21st century version of Star Trek's replicators and they can, literally, print (or replicate) anything from a piece of pumpkin pie to a full-blown multi-story house. But 3D printing is not just one thing – there are many ways to do 3D printing. This slideshow illustrates the nine most common 3D printer technologies.