Is it there for aesthetic value or something more? If you live in the U.S., you're familiar with the holes in the prongs of electrical plugs. Many, if not most, American plugs have them. So what ...

Not all outlet holes are the same, and there's a reason for that. The shapes (vertical slots, round holes, T-slots, etc.) correspond to specific electrical functions and safety features. Take the ...

close up of Type A plug prongs - Gabriel Lopez/Shutterstock If you've ever stared at the holes in an electrical plug and wondered why they exist, you're not alone. Like an industrial-age kōan, the ...