My favorite non-design object

Rainbows are not designed. They can be found in nature and they are so beautiful.

These beautiful optical illustions are created by reflection and refraction of light in water droplets. After rain or next to a waterfall, water droplets act like a prism and separate the white sunlight into its spectrum of colors. This effect happens because of the difference in wavelength of the different colors. Each color of the rainbow refracts at a different angle, but they all come from the same white sunlight which contains all the seven colors. The longer the wavelength, the bigger the angle of refraction the color has. This is why red is always on the outside of the rainbow. How big the rainbow is depends on the refractive index of the water droplet. Sea water has a higher refractive index, so the rainbow next to the ocean are smaller than rainbows made by rainwater. You can find more information on rainbows on National Geographic.