system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: why do we see colors and patterns when we close our eyes?
gpt
Your eyelids may be closed, but your eyes are still on. You're looking at the back of your eyelids and whatever light that is seeping in. Skin is made up of tiny patterns. Also, when there is a lack of light, our brains try to fill in the gaps. If you've ever tried a psychedelic, closing your eyes will produce the most visuals.

Sorry for the shittyELI5.