Memento

How this film uses it

Nolan runs the color scenes in reverse order, so each scene ends where the previous one began. You feel as lost in time as Leonard does. First, you know what happens but not why. Then you learn why, but you have lost track of what happened. The structure is pretty much the disability itself.

Where to see it

The film's opening. It plays backwards, and you are dropped straight into Leonard's out-of-order world.

How this film uses it

Leonard's polaroids with handwritten captions, his tattooed facts and his annotated notes add up to a memory system. The film shows that it can be gamed. Anyone who understands his condition can rewrite his reality by tampering with his notes. This outside memory is less reliable than the memory in his head that it replaced.

Where to see it

Leonard writing on a polaroid. Writing things down turns out to be a way of making up the facts, which is very different from recording them.

How this film uses it

The black-and-white scenes run forward in time from a fixed point, while the color scenes run backwards. The 2 strands meet at the end of the film, which is the middle of the story in time order. You have to keep both directions in your head at once to put the full story together.

Where to see it

The color and black-and-white strands meeting. This is the moment the 2 directions of time join up.

How this film uses it

The final reveal is that Leonard may have already found his wife's killer and chosen to forget, so he can keep hunting. In a normal mystery, finding the answer is the fun part. Here, it becomes something far more disturbing. He can't remember, and the horror is that he might not want to.

Where to see it

Teddy's revelation in the final stretch of the film. It raises the possibility that Leonard has been inventing his own purpose.