system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does a boomerang return to you after you throw it?
gpt
A returning boomerang is made like a 2 or 3 wing propeller with uneven wings. When you throw it spinning it creates lift at almost a right angle to its surface (because the wings are uneven).

So if you throw it level to the ground it will just go upwards while it flies away from you until it slows down so much that the gravity is stronger then the lift and then it falls down.

If you throw it at an angle to the ground it will try to fly in a curve or a spiral. So you practice changing the angle until you learn how to make the path to go towards you.

You can also change how strong rotation you will give it while throwing so you can time the moment it goes near you with the moment it starts to fall down, if done right the boomerang can be made to almost stop right in front of you.