system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why, when you rub your eyes really hard, you are transported into a swirly pattern galaxy?
gpt
You stimulate your retina when you rub your eyes which causes it to produce some sort of visual noise. 

Try looking to one side as far as you can with your eyes closed. Then slightly touch your eyeball through your eyelids on the edge of the opposite site for some circular visuals. :)

Edit: eyes closed all the time.. It ia not neccessary to touch your eyeball directly ;)