augmented reality has quietly become one of the most familiar pieces of technology most people use without ever calling it by name. if you have ever pointed a phone at your face and watched a pair of sunglasses settle perfectly onto the bridge of your nose, or seen a sofa appear in your living room before you bought it, you have used AR. it is the layer where the digital world is registered onto the real one in real time, so convincingly that the two appear to share the same space.