An experiment with the LED sensor of an Arduino, linked to Processing graphics:
inverted pulsating cat’s eye
When the light is high, the pupil of the cat’s eye widens,
when the light is low, the pupil of the cat’s eye closes.
[I know in reality, it’s the other ways round… ;) ]
--> The color of the pupil also changes, from bright (high value) to dark (low value)