What an unfortunate coincidence!

This year, the Orthodox Easter coincides with the Catholic one.

Canadian Thanksgiving Day and Columbus Day in the USA coincide, so Esperanto speakers from both countries take this opportunity to have an international meeting.

In addition, coincidences inevitably come in threes.

Was that a coincidence, too?

That's pure coincidence.

I think it's just a coincidence.

Do you think that was just a coincidence?

I don't think that's a coincidence.

That wasn't a coincidence.