Every method is used for creating reality of illusion.
Those are utilized for giving reality and reliance to people and that lives in this world, the color and the sound are one of them.
Though color and sound have some meaning, first let's talk from there.
As you know, if the world that you live doesn't have light, you can't see anything, and maybe you doubt even your existence.
Further if you can't hear voice as a sound indicating other existence, and if you can't see the individual, it is difficult to understand these exists.
If all of colors and sounds are lost, it is difficult to form real society.
I updated message "What is the color and the sound（short version）" on pixiv.
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