Re: this time with the correct polarity
Once upon a time you could tell the way the A[A[A]] batteries went in because there was always a bump in the housing for the "+", and always a little springy thing for "-".
Nowadays, however, I am seeing some (e.g. even xbox controllers, not just random cheap crap) with the same physical arrangement - bump & springy thing - but tiny labels saying which way round they go, and not even consistent in the same device; so now you have to peer carefully just in case. It's CFI.