I’ve found it interesting that the range of visible light for humans has the highest frequency roughly double that of the lowest frequency. Working by analogy to sound, we essentially see one “octave” of light and if we perceived frequencies into infrared or ultraviolet, they would perceptually look like variants of the color at 2× or ½× the frequency (which suddenly makes the adjacency of violet and red on the color wheel make sense). I kind of wonder whether anyone has ever made a camera that doubles or halves as appropriate light frequencies beyond the visible spectrum to make them visible. It would be interesting to see what the world looks like extending the range in either direction.