Varieties of palindromes in poetry

My posting for October 6 mentioned palindromes. Today we continue with the topic, including illustrations of the various ways they may influence poems.  A number such as 12345654321, which reads the same if its digits are reversed, is the sort of palindrome one encounters in arithmetic.  Palindromic poetry includes more variety.  These sentences, taken from a list compiled by Ralph Griswold, are samples of palindromes in which the unit is a single letter.