I had a classmate in secondary school with whom we seem to have shared a very similar brain wiring to the point where we wrote identical tests in physics. I believe for maybe two years. As soon as he got his result, I knew mine & vica versa. Was a strange experience, we did develop a special bond.

We were never accused of cheating, it was a tiny group though (20).

Edit: By identical, I do mean _literally_ the same mistakes, same points. Not 99% similar. 100%.