Mirror Images — Definition

Definition

A mirror image in a diagram-reasoning question is the reflection of a figure across a specified line. For the usual vertical mirror, horizontal placement reverses relative to the line while vertical placement remains unchanged.

Each point and its image are equally far from the line on opposite sides. This is different from a half-turn, which changes both horizontal and vertical placement around its centre. The reference line and exact marked shape matter: a symmetric outline can contain asymmetric details, and a familiar letter's appearance can vary by font.

Coordinates or clearly described markers make the intended transformation unambiguous.