Since Cleolinda mentioned ambigrams a while back, I have been trying to make some up. I'd ask if you would want to see my sketches (does that line work?) but they are just scribbles while I work out the letter shapes. So I made a few of them to show
Ambigram n., - a word or words that can be read in more than one way or from more than a single vantage point, such as both right side up and upside down. (from Latin: ambi=both gram=letter)
Some are trickier to do than others, and I have some more to work out.