Purple
There was no purple in Oz, Dorothy noticed. There was green, yellow, red, and blue, but no purple.
She wondered why. Did the Munchkins, with their land of blue, and the Quadlings, their country red, not get along? Or had no one ever thought to mix red and blue and see what happened?
"Citizens of Oz," she called, "before I go I'd like to show you a new color!"
They were interested at once. A new color, one beyond the ones they'd known?
"It's called purple…you get it by mixing red and blue…here, I'll show you!"
She showed them. And they showered her with praise. Dorothy Gale, killer of two Witches, savior of Oz…and the discoverator of the color purple.