I heard that the violet in rainbow is only created because the bottom blue coincides with another inner rainbow’s top red. I forgot where I heard it but it sounds logical.
Whenever I see the EM spectrum, it always goes from red to green to blue then to VIOLET which I don’t know how it got there. What bothers me more is how there’s an infraRED and then it goes ultraVIOLET.
I remember in preschool that red + blue = violet so where did the red from the violet part of the spectrum comes from?