The first key to thinking about 3-D printers is this: Do not think printer. Think magic box that creates any object you can imagine.
In the box, razor-thin layers of powdered material (acrylic, nylon, silver, whatever) pile one on top of the other, and then, voila — you've got a shoe, or a cup, or a ring, or an iPhone case.
It's miraculous to see. Press a button, make anything you want. But just how important is 3-D printing? Unlike earlier big-deal technologies (like, say, the tractor) 3-D printing won't really replace what came before.
At a clean and sunny community center in Seoul, the South Korean capital, senior citizens make clay models of their own faces in an arts class. Some of the faces are vivid and lifelike. Others are expressionless and indistinct. The project is intended to help the seniors remember what they look like.
This is the Gangseo District Center for Dementia. Since 2006, Seoul has opened a dementia center in each of the city's 25 urban districts.