Interwoven into the scarf material are pixels containing red, blue and green light-emitting diodes (LEDs), so adjusting the brightness of each type of diode turns the scarf a different overall shade. —Chameleon scarf coordinates with your outfit (NewScientist.com (will expire))
O brave new world, that hath such gadgets in it!
(I Googled for photos but I found none. Thanks for the link, Rosemary.)