Oh ffs. It's not impossible for two or more people to think of the same thing. This is what I tell myself whenever I see my old designs plundered for whole phrases. -.-; I wouldn't feel so irritated if they'd give credit but oh well.
Anyway, it really is totally possible. What's-her-face.. Beca? I have no idea why I think that's her name.. anyway. Both of us submitted designs to the Nalea gown contest and then when Nalea was actually giving them out, we both pulled out our design lists and exchanged in a chat. At least five or six designs were nearly word-for-word the same and we'd never discussed it at all.
It happens.