It isn't clear on whether or not you will need a specific design (or at least the frame of a design) when your LED tattoo will be "inked" on your skin, since the object can move/stetch, but it definitely gives me a good reason to figure out what I would want!
Taken from Wired.com:
Researchers from the University of Pennsylvania have created new LED tattoos - there are developing silicon-and-silk implantable devices which sit under the skin like a tattoo. Already implanted into mice, these tattoos could carry LEDs, turning your skin into a screen.
The silk substrate onto which the chips are mounted eventually dissolves away inside the body, leaving just the electronics behind. The sheet of silk will keep them in place, molding to the shape of the skin when saline solution is added.
These displays could be hooked up to any kind of electronic device, also inside the body. Medical uses are being explored, from blood-sugar sensors that show their readouts on the skin itself to neurodevices that tie into the body’s nervous system — hooking chisp to particular nerves to control a prosthetic hand, for example.
Chips are already used inside bodies, most notably the tiny RFID tags injected into pets. But the flexible nature of these “tattooed” circuits means they can move elastically with the body, sitting in places that a rigid circuit board couldn’t.
