Thank you for expressing your concern about color. About purple, recently I've been looking at pictures of rainbows, and one in particular caught my attention,

Thank you for expressing your concern about color. About purple, recently I've been looking at pictures of rainbows, and one in particular caught my attention, it shows several (I believe 5) concentric rainbows. The order of the colors alternate on each rainbow, so of the outermost rainbow has red on the outside, the one right next to it has blue on the outside and red on the inside. Then if you look at the intersections or the space in between rainbows, it looks purple. What makes that space look purple? And what makes the color order alternate?