Chameleon inspires 'smart skin' that changes color in the sun

A chameleon can alter the color of its skin so it either blends into the background to hide or stands out to defend its territory and attract a mate. The chameleon makes this trick look easy, using photonic crystals in its skin. Scientists, however, have struggled to make a photonic crystal "smart skin" that changes color in response to the environment, without also changing in size.