Jeff Stallar

I downloaded this a few nights ago. What a great tool! I particularly like zooming in on airports. Oh, and check out the grand canyon! From above, it's uninteresting, but then tilt down and watch it turn 3D!!

A mechanical device is something that takes energy input, modifies it, then outputs it in such a way that it assists in the performance of a task. A lens takes light input, modifies its vector, then outputs it in such a way that assists the performance of the eye. So is a lens a mechanical device? I think so, but I'm having a hard time convincing a friend that glasses are mechanical devices. He keeps saying it must have moving parts to be a mechanical device.