Wittgenstein on color, remark #10

Someone who has learned to find or to mix a shade of color that is more yellowish, more whitish or more reddish, etc., than a given shade of color, i.e. who knows the concept of intermediary colors, is (now) asked to show us a reddish-green. He may simply not understand this order and perhaps react as though he had first been asked to point out regular four-, five-, and six-angled plane figures, and then were asked to point out a regular one-angled plane figure. But what if he unhesitatingly pointed to a color sample (say, to one that we would call a blackish brown)?