Mirror writing is the ability to write from right to left, reversing each letter so that when it's held to a mirror, it reads normal.
I'm a mirror-writer, and have been since I'm a kid. I'm not really sure how I got into doing this unusual thing, but it came very easy to me. I'd write notes and letters to friends, which required them to hold it up in a mirror to read it - or turn the page over and hold it up against a strong light if I didn't write on both pages. Silly and entertaining, I never really thought much of it until I read some research on the subject.
Mirror-writing has genetic links. Studies in neuroscience suggest that those who mirror-write have bilateral language centers, with one in each hemisphere of the brain. Approximately 1 in 6500 can mirror-write, the most famous of them all being Leonardo Da Vinci.
I found a reverse writing generator that comes very close to true mirror-writing. You can write regular text and then have it reversed, flipped or written upside down. The fun thing is seeing that no matter how the letters are arranged, our brains are wired to make sense of the words.
Have fun with it. ti htiw nuf evaH