Digital Pigment Assistant

There exists, in Nature, a serendipitous link between pigment and time, not unlike a Liquid Crystal Display. But first, let me take you on a patronising scientific journey...

Consider, the small matter of pigment. Let us ignore, blood flow and Carotene for the moment, and say that the colour of our skin is determined purely by the pigment Melanin. This wonderful substance has allowed many essentially-identical human beings to oppress and kill each other for centuries by focusing on a superficial difference :- but, I digress... Melanin is produced in sub-cellular organelles called Melanosomes located within specialised skin cells known as Melanocytes. The amount of melanin increases in response to sunlight (i.e. tanning) and genetic heritage. Voila - a Liquid Pigment Display.

Now all we need is a clock - enter the Pineal gland... The Pineal gland or "Third Eye" is located just behind the regular eyes and responds to seasonal factors, such as the amount of daylight and the availability of LSD (see link). It produces two chemicals; Seratonin, and by happy coincidence, Melatonin. These are produced in a regular oscillating beat known as the "Circadian Rhythm". Melatonin directly effects melanocytes, inhibiting the production of melanin...

To take advantage of this, I propose a tattoo that helps you remember important dates, such as anniversaries and tax returns. The tattoo in question would display a date and message in a prominent place thus removing any need to write notes on the palm of your hand with a pen.

Taking some basic scientific notions, and ignoring many others, one could 'morph' from one digit to another just like a cheap wrist-watch. Given the almost unlimited supply of skin that some Americans possess, it would also be possible to create much longer messages than Cell phone SMS technology currently allows.

To summarise, we need a "Fourth Eye", a Digital Pigment Assistant (DPA) [patent pending] located at or near the palm of your hand.

note: This won't work in cold climates (lack of sunlight, gloves, etc)...