Image Inversion

[Poplar]

Image Inversion without a lens

[LiIIabet]

A mirror. There is no preferred plane of rotation, so it itself is a form of 'inversion'.

[gen2]

I think Poplar needs this for a Telegraph crossword and the answer is Pin-hole Camera

[brachiopod]

It would be nice if the question was put into some sort of context.

Come to think of it, it would be nice if there were some sort of question, (in an interrogative statement kind of way).

[Hammer]

It amazes me that people expect others to spend some time and effort answering a question, but they can't even be bothered to ask it properly.