More than 15 years ago, David Barnett was working as a philosophy professor at the University of Colorado when he came across a problem. His headphones kept getting tangled up. He ventured to a Joann fabrics store, where he bought two buttons he glued to the back of his phone; he would wrap the wire around them. Problem solved! Or at least he thought so—until he realized how ridiculous it looked, and searched for a more elegant solution. When he…