system
Given the following post, respond as if you're commenting on Reddit:
human
Why does looking through a tiny hole make things focus?

When I forget my reading glasses and need to read small print I can curl up my forefinger (like making a fist, but only my forefinger) tight enough to leave only a tiny pinhole in the center of my curled finger. If I look through that tiny hole by putting the finger very close to my eye this makes the print come into focus.

Why? How does this work?
gpt
Focusing just means taking light rays that have slightly different directions and making them all meet at the same point. 

When you look through a tiny hole, only the light rays that were already going to meet at the same point get through. The light is already focused.