At the Vienna Institute of Technology, a group of engineers claims they've created not only the world's smallest 3-D printer, but also one that's so light and inexpensive that it could conceivably pave the way for truly domestic 3-D printing. Lost an earring or a cuff-link? Print one out (and congratulations on your fancy life). That's the future, and it might not be far off at all.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.