Robert A. Freitas and Gina “Nanogirl” Miller have developed an animation of the “programmable dermal display” described in Freitas’ Nanomedicine, Volume I: Basic Capabilities book.

A population of about 3 billion display pixel robots would be permanently implanted a fraction of a mm under the surface of the skin of the back of the hand, presenting to the user data received from the large population of medical bots that roam the user’s body and conveying instructions from the user to the bots by finger-tapping on the skin.

Source: Dermal Display