Watch as an autostereogram fades from comedy mask to tragedy mask to star to tragedy mask to comedy mask. Note that the structure of the 2‑D pattern stays fixed and that only the colors change. This is because the comedy mask is encoded using only variations in lightness; the tragedy mask is encoded using only variations in hue; and the star is encoded using only variations in chroma. The transitions you see in the video work by gradually converting all pixels' lightness to 25% then gradually converting all pixels' hue to 0° (red).