# Mirror and letters

by Numeriprimi
Tags: letter, mirror, overturned
 P: 138 Hello. I have got basic question for you. Can you explain it simply? Why are the letters in a mirror overturned on left-right and not upside-down? Thanks. And sorry for my bad English.
 Mentor P: 17,541 They are not turned left-right. The left-most letter is still on the left and the right-most letter is still on the right. When a person turns to face you the left-most letter is on the right and the right-most letter is on the left. Mirrors do not switch left-right nor do they switch up-down. When people face you they do switch left-right but not up-down. That is why mirrors seem strange left-right but not up-down. They are strange because they do not do a turn that we are used to seeing people do.
 P: 999 A mirror reverses front and back (*). This means that the three-dimensional symmetry of an image in the mirror has been reversed; a mirror image of a right hand looks like a left hand and vice versa. A front-to-back reversal is identical to a left-to-right reversal coupled with a 180 degree rotation. Either interpretation is valid. As Dale points out, the interpretation that feels natural is a left-to-right reversal with a 180 degree rotation. (*) Where "front" and "back" are referenced against the plane of the mirror.
P: 34
Mirror and letters

 Quote by Numeriprimi Hello. I have got basic question for you. Can you explain it simply? Why are the letters in a mirror overturned on left-right and not upside-down? Thanks. And sorry for my bad English.
From the man himself: