They're useful for more than just messes.

If you have watched Star Wars, you may recall R2-D2, the droid that could do anything from navigating the ship to hacking ...

It’s 3 a.m. in San Francisco’s Tenderloin district, and an all-night, drug-fueled party has been raging for hours. The sidewalks are littered with trash and human feces. Addicts huddle in the alleys, ...

Unless you’ve spent the last few years locked indoors and had all of your goods delivered to you — a not entirely implausible ...