system
Given the following post, respond as if you're commenting on Reddit:
human
Why are magnets U-shaped?

I realise not all magnets are U-shaped, but why are they commonly illustrated as the "classic" red 'U'?
gpt
I don't know where the red came from, but there are two advantages to the U shape:

1) Both poles face the same direction, which provides you with the most force to pick up a piece of iron. This is because the magnetic field is strongest at the poles.

2) Between the legs of the U, there is an approximately homogeneous magnetic field. This makes interpretation of experiments very easy, because homogeneous magnetic fields are the easiest to work with theoretically.