When you look at a mirror, the words are laterally inverted. It is not the same as just reversing the letters. For example if you reversed the letters in 'cantonese opera', it would look like this ... arepo esenotnac .
However, if you look at its image in a plain mirror, it would be like this:
This is called lateral inversion.
I remember studying about lateral inversion when I was in lower secondary. I found it quite fascinating.
Now, look at this photo. Where is the mole? It is on his left cheek. But if this photo was the image in a mirror, then the mole is actually on his right cheek.
Another one ... I love YAM? Again if this photo was taken off a mirror, then it is I love MAY.
When does a right-handed man become a left-handed man?
When you look at him in a mirror using his hand to write.