There's a ball of yarn sitting pretty as can be It isn't really there, it makes an alright simile It's purple all around, you know because it's what you see You know just what it's good for - exactly what you perceive Hold it in your hand and unravel just a piece Here's something you didn't know, the color slipped right into green Now you know simply everything, so now you're simply bored You walk away never knowing - what color is the core?