Palindromes are also found in words and sentences. Usually, formatting and punctuation are removed, and only the letters themselves are figured, but the principle of reading the phrase or word forward or backward, is still the same as what we've been dealing with.
For example: Madam, I'm Adam is an example of a sentence palindrome. radar would be an example of a word. Now, in my opinion, there are very few sentences, that work well as a palindrome. Take the following for example: Pull up if I pull up. is just fine with me. So is: A Santa lived as a devil at NASA. However, On a clover, if alive, erupts a vast, pure evil; a fire volcano. It just doesn't have a flow to it!! Maybe I'm not poetic enough....
I think my favorite though is "Do geese see God?"
Now, I appreciate the effort that people spend trying to come up with these things, but they just don't hold my attention very long.
If you want to read a bit more on them, I'd direct you over to: Jim Kalb's Palindrome Connection.
As for me, the numeric type holds more interest. Maybe it's because they are simpler to understand! :-)