system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: what is an eigenfunction and how does one work?
gpt
A totally not mathy explanation for a five year old to  (hopefully) understand.  Imagine a magic box where you throw in different shapes.  You can throw in anything, a cube, a ball, a pyramid shaped thing, anything that fits in the box.  When you close and shake the box and open it back up, you will see another object inside. Maybe a blue pyramid gave you a green cylinder.  But if the ball is the "eigenfunction" of the box, then throwing in a ball will give you out the same ball but maybe a bit larger or smaller and another shade of the same color.