Placed on a forehead, the device can record brainwaves; on the wrist, blood flow and muscle movement. On the skin of sick patients, it can track vital signs and watch for problems, replacing the bulky equipment usually found in hospitals. And stuck to the throat, it can function as a secret cell phone, activated by the movements of a person’s voice box.

Temporary tattoos use a simple and inexpensive way to adhere, or stick, to skin: a good sticky backing that stretches and flexes with skin’s natural motion

Todd Coleman