There are symbols all around us that we take for granted, like the lightning strike icon, which indicates that something is high voltage. Or a little campfire to indicate that something is flammable. Those icons are pretty obvious, but there are others that aren't so straightforward. Like, why do a triangle and a stick in a circle indicate "peace"? Where does the smiley face actually come from? Or the power symbol? We sent out the 99PI team to dig into the backstory behind some of those images you see every day.