system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: how do boomerangs work?

Why does it return? What about it, physically, makes that happen?
Can you change the curve to alter the trajectory and still have it return?
gpt
What you're referring to are "returning boomerangs" - in fact the first boomerangs used for hunting by Aborigines were non-returning boomerangs. Anyways, in relation to returning boomerangs:

1) As the boomerang spins through the air, the wing at the top of the spin is moving through the air at a faster rate than the wing at the bottom, because it is moving in the direction of the throw while the wing at the bottom is going the other way. The result is that the top portion will generate more lift than the bottom portion as it cuts through the air.

2) The difference in lift between the top and the bottom then creates a torque which ends up tilting the plane of rotation slightly such that the boomerang ends up flying in a curved path through the air. Since the torque applied here is going to be reasonably constant through the short flight of the boomerang and the angular momentum likewise stays relatively constant, the boomerang will fly in something of a cone pattern; thus, if thrown correctly and wind or the like doesn’t interfere too much, the boomerang will come right back to you.