Inspired by @Katoi's declaration of love for camera trickery, I've been thinking about some of my favourites on a particular theme: the ambiguous mirror. Here's a good example from Ghost (a lovely film in many ways, and 30 years old as of yesterday).

Jean Cocteau got there early and threw all sorts of inventiveness and imagination at the task. Of course, Cocteau was one of the very best at bending the inherently representative, realistic tools of cinema towards impressionistic, poetic, even oneiric ends.

Alain Resnais' cubist cinema saw him mess with time, space and their overlaps in many ways. It might take a moment to work out where the mirroring is and isn't in this shot from Je T'Aime, Je T'Aime.

If I'm not mistaken, Chris Smith used a little 'CG smudging' to slightly mess up his classical in-camera trickery for this shot from Triangle.

When it comes to the 'Groucho stunt' of having two actors - one playing the reflection and one as the 'original' - it rarely gets more fun than Evil Dead 2. A great shot from an all-time classic sequence of lower-budget, higher-wit creativity.

Arguably the mirror trick to end them all is from Robert Zemeckis' Contact but this really doesn't belong in a compendium of in-camera tricks. Let me cheat and say that, seeing as we're going through the looking glass here, normal rules can't apply.

Building two versions of the same room and putting nothing between them is a timeless classic. Here's Coppola's take on the trick from Peggy Sue Got Married.

James Cameron's version of the same trick allowed the Terminator to go to pieces.

While Christopher McQuarrie used the no-mirror technique to give Mission: Impossible masks a remarkable level of realism - by having the latex face be played, in camera, by a real one.

Pulling this trick off properly required some careful production design - including flopped typography on book spines.