On a separate Oumuamua question (Oumuamua alien space junk?), I was confused how shape could be inferred from a single pixel, per another user's (@Uwe) comment. It was suggested I ask this question here.
If all we've observed Oumuamua as is a single pixel, how can its elongated shape be deduced from that? How can any non-uniform shape be deduced from a single pixel?