The process of 3-D printing uses computer-created digital models to create real-world objects -- everything from simple toys or jewelry to more complex objects with moving parts.
According to Reviel Netz, a classicist at Stanford University who is working on the palimpsest, the original uncorrected diagrams suggest that Archimedes was more concerned with the mathematical arguments his geometry gave rise to than with the real-world behaviour of the objects he wrote about.
At their core, these 3D printers are not unlike their 2D counterparts, offering a way to translate images on computer screens into real-world analogs -- only in this case they're objects you can hold in your hand.