anybody wants a key ? <| sep |> Would you say your TV screen is only green red and blue ? Because that ' s the only 3 colors of pixels in the monitor . If you say no , there ' s a whole rainbow of colors produced by a TV , then you should reconsider what constitutes conditions around an object vs conditions within an object . If you put yellow pigments next to blue pigments , you ' ve got two separate colors . Then put them closer and closer together until they ' re on top of each other , then what ? Would you say they ' re still two separate colors or would you say they ' re green now ? You ' d probably say that green has been created . Same thing with a rusting fence the fence has turned brown , it ' s not somehow separate from the rust and still silver . It ' s changed color . What about thermochromic materials that change color with heat ? Is that a more legitimate color changing process than a rusting fence ?