How do you get teenage girls interested in coding? Simple, give them new ways to call out friends and enemies in social scenarios. At least, this seems to be the idea behind Jewelbots, a new line of programmable friendship bracelets that light up and vibrate when other Jewelbots are near. BFFs can assign one another custom callsigns using the iOS and Android app, and when they meet, their bracelets will pulse and buzz in tandem. Or, if they don’t light up, well, you’ll know that Stacy just cut you the hell out of her life.