A collection of alphabetically-arranged letter quartets are offered below, each of which admits a rearrangement that will yield a pair of five-letter words when an "A" and an "O" are inserted in the same location.
"Ohs and Ahs,"
Word Ways: Vol. 46
, Article 16.
Available at: http://digitalcommons.butler.edu/wordways/vol46/iss2/16