However much you like the idea of a wearable electronic patch monitoring (or improving) your health, it's not all that practical. Making just one patch using current tech can take days, and you'd better believe that the result will be expensive. University of Texas researchers may have licked this problem, though. They've developed a "cut-and-paste" manufacturing method for tattoo-like patches that whittles the assembly time down to 20 minutes, and should reduce the cost in the process. The technique involves little more than cutting shapes out of metal placed on polymer sheets, and then printing the electronics on to polymer adhesives. Effectively, it's 3D printing in reverse -- you're taking material away until you get the design you want.