The set (0,1)∪(1,2) is open, but is not regular open, because its closure is [0,2], so the interior of its closure is (0,2).

On the coasts of South Carolina, Georgia, and northernmost Florida, maritime forests are dominated by live oaks (Quercus virginiana), and occur as large contiguous patches of forest on barrier islands, the immediate mainland, and as small patches (oak hammocks) scattered among coastal marshes.

And a rock that would fall on it for good measure, which couldn't be dug up because no one would want that particular nontreasure.

Have you ever written “PS” at the end of a letter? If so, you've used Latin words. “PS” stands for the Latin words “post scriptum”, or “after the writing”.