Glide reflection
= Glide reflection
A glide reflection of the plane composes reflection in a line with a nonzero translation parallel to that line. It reverses orientation and has no fixed point. It cannot be one reflection, because a reflection fixes a line, or a product of two reflections, because such a product preserves orientation. The <finite reflection decomposition of a Euclidean isometry> therefore shows that it requires exactly three reflections.