Pink Floyd’s Dark Side of the Moon cover, voted the greatest classical rock album of all time, intended to portray the prism and dispersion of light into a rainbow as a certain metaphorical symbolism and a light show that was never celebrated. However, they really were not aware of the fact that this image would be used by many to help illustrate the concept of refractive index and how light changes speed and direction when it encounters a different medium.
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Source: Phys.org