A palindrome is a word, phrase, number, or other sequence of characters which reads the same backward or forward. Allowances may be made for adjustments to capital letters, punctuation, and word dividers. Famous examples include "A man, a plan, a canal, Panama!", "Amor, Roma", "race car", "taco cat", "Was it a car or a cat I saw?" and "No 'x' in Nixon". Composing literature in palindromes is an example of constrained writing. The word "palindrome" was coined by the English playwright Ben Jonson in the 17th century from the Greek roots.

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