Answer: Lateral inversion is the actual or imagined reversal of left and right. The letter d is formed when the letter b is turned laterally (more or less). The visual lateral inversion that a flat mirror cause is well-known. A mirror flips a three-dimensional object in a direction perpendicular to the mirror surface.
As a result, we frequently perceive the change as a left-right reversal due to various factors. The right side of your mirror image, for example, is exactly opposite you. There is no left-right reversal in this sense. However, unlike in the mirror, you usually don’t see your front and back sides reversed. As a result, the left-right axis of the “person” you see in the mirror appears to be reversed. If you think of letters as two-dimensional objects, there appears to be no shift perpendicular to the mirror surface, but lateral inversion may be observed.
This is usually expressed in how the mirror changes the location of the letters about the spectator. The inversion of images in the mirror is known as lateral inversion. When the picture on the mirror is up-right, and items on the left side appear on the right side, this is lateral inversion. That is why we see “ambulance” written in lateral inversion because it looks to say “ambulance” when viewed through a car’s rear view mirror.