Are you use that the odd one out is heavier or lighter? I think it's apparent how to determine which ball is heavier than the others, but if it could be heavier or lighter, I don't see how you can get enough information in two weighings.
Thank you for this. It will always be heavier. The goal is to find a method to figure it out 100% of the time which is the heavier one. I will update the descrption.
