Just an interesting observation I’ve had, and if it’s not already a problem/theory/whatever, I think it should be. Also, it’s car related!

Imagine a wheel, made from a perfectly uniform material. Say it has eight evenly-spaced spokes. It’s perfectly balanced, and it’s possible to be made lighter by removing spokes. You can remove four or six spokes to keep it perfectly balanced.
But then take a seven-spoke wheel. It’s impossible to remove any spokes without throwing it out of balance. This is true of any prime number.

Basically, for any composite number of spokes, you can symmetrically remove any amount that will leave one of that number’s factors (excluding 1), and the wheel will remain symmetrically balanced.

Is this useful in the real world? No. Is it useful in math? Still not really. Is it an interesting way to look at prime numbers? Hell yeah!