In the classic tradition of the famous SATOR word square. I present at the left one example of what may be considered a definitive English-language reversal square -- if you accept my argument. All the words used are perfectly valid:
"Drow Rot or Word?,"
Word Ways: Vol. 29
, Article 20.
Available at: https://digitalcommons.butler.edu/wordways/vol29/iss1/20