Ring and hair strand gender prediction??

Soooo which is it...if it goes in a circle it’s a boy and back and forth is a girl?? This is what I’ve heard but then I heard it’s the opposite...so which one is correct?? First pregnancy it went in a circle over my belly and then I had a MC and was curious and did it again over my empty belly and it did not move!!! I just now did this again at 8 weeks and it’s moving in a circle again. I’ve also done the same thing going back and forth between my fingers and it also went in a circle every single time I did it.