Every once in a while, you see a piece of cool technology that a) just works and b) looks so incredibly simple, elegant and obvious that you wonder why it took so long to create.

In this case, I'm talking about the monocopter, developed by aerospace engineering graduate students at the University of Maryland's Clark School of Engineering.

For decades, engineers have been trying to mimic and improve upon nature's design of maple tree seeds (a.k.a. samara fruit) and the spiraling pattern they make when they fall to the ground. (Remember playing with those as a kid? I sure do.)

The school, in a press release, said engineers since the 1950s have tried to mimic the spiraling fall, with little success. It was hard to build a small craft that could be controlled with precision. Until some UM students and faculty came along.

They were able to build a small craft -- with one rotor -- that could take off from a stationary position and hover, and be remotely controlled. (Here's the project website.) It's incredible to watch, and it's billed as the world's smallest single-winged rotor aircraft. Expect this technology to show up for use in defense and emergency situations.