Rule explicitly prohibits anodizing, painting, dyeing, or changing the color of any legal VEX part. This move is likely tied to the game’s heavy emphasis on AI Vision and Optical Sensors; the GDC wants to ensure sensors can reliably identify objects without being confused by robots that look like Field Elements, Scoring Objects, or other distracting colors. You can still use non-functional decorations for aesthetics, provided they don’t mimic game elements or interfere with opponent sensors.