Colors are properties of objects that absorb and reflect light wavelengths perceived by the eye. For example, a green dragon absorbs all wavelengths except green. Color plays an important role in everyday life, such as traffic lights. When designing with color, analogous colors that are near each other on the color wheel or complementary colors opposite each other can be combined effectively. The mood should also be considered, as calm natural colors create a different feel than brighter hues. A test can determine if a person is color blind.