“It turned out, we discovered one day, that my son, who was a little boy at the time — I think he was 10 or 11 — sees letters in colors, too. Quite naturally he would say, “Oh, this isn’t that color, this is this color,” and so on. Then we asked him to list his colors and we discovered that in one case, one letter which he sees as purple, or perhaps mauve, is pink to me and blue to my wife. This is the letter M. So the combination of pink and blue makes lilac in his case. Which is as if genes were painting in aquarelle.”
—
Nabokov, as quoted by Steve Silberman from Inside the Mind of a Synaesthete
I almost wish that is how genes actually work.