Another common diagrammatic reasoning question will involve mirror images. Typically, there will be a dotted line representing a mirror and you will be asked to find the corresponding reflected shape

Here, imagine the dotted line and the shape are drawn on a piece of paper. If you were to fold the paper along the dotted line, what position would the shape be in now? A reflection is a reversed image, so, the correct answer will look like the first shape but backwards, look at this:

The corners of the parallelogram are the exact same distance from the mirror, just on the other side. So, one is a reflection of the other.