What do you do if you want to 3D print in any direction, but can't buy a pre-made pen like the 3Doodler? If you're Vimal Patel, you build your own. He melded a hot glue gun with a powered Lego mechanism (really, Technic) to extrude filament in any axis. To call it bulky would be an understatement, but it works -- as you'll see in the video below, it can produce fairly complex objects as long as you have a keen eye and a steady hand. And if you want to try it, you can. Patel has posted his Lego Digital Designer file for the 3D printing gun, so it shouldn't be too hard to replicate the invention at home.