Technology that's totally impossible

It all started with the printing press around 1440, and ended up with the HP Laserjet 4 making constant, enigmatic requests for users to "PC LOAD LETTER". Although printing is a remarkable step forward for humanity, it's easy to understand how the process works -- essentially some kind of ink gets stuck on some kind of paper. The problems with plausibility arise with 3D printers.

Yes. That's right. We said 3D printers.

It's now somehow possible -- certainly though magic -- to print three-dimensional objects using a special printer. What's more, these printers can print more printers, and you know what that means, right? That's correct: one day there will be printers as far as the eye can see. And each one of those printers will print more printers. And those printers will print more printers. If you've seen the Star Trek episode 'The Trouble With Tribbles', that's what's going to happen to us. With printers.

To be fair, the process behind 3D printing is reasonably straightforward. They use a variety of technologies to achieve their goals. For the most part, they share the technology of the inkjet printer. Instead of ink, they build layers using a photopolymer. A UV lamp fixes the layer, and then the process begins again. The printer-printing printer we mentioned earlier is part of open-source project RepRap, the goal of which is to provide everyone access to three-dimensional printing.

With scientific research galloping ahead, it can't be long before we can print things made out of metal, and then we're in big trouble. Can you say Skynet?