The house is green, the sky is gray, the fire engine is red.

FORBES: Egyptian Virginity Tests, America's Shaming Wand and Trudeau's Satire

Clearly intended as a consumer product, the EM-500 is available in five colors: yellow, blue, green, red and sky blue.

CNN: Review: Design makes the difference for pocket-PC gadgets

But a clear, cloudless day-time sky is blue because molecules in the air scatter blue light from the sun more easily than they do red light.

BBC: rainbow