A given word is split into two parts which may, or may not, have the same number of letters. A common letter (A to Z) is positioned at the front of each of the two groups of letters to form two words which, ideally, make a 2-word phrase.
"Adding Two Like Letters,"
Word Ways: Vol. 52
, Article 6.
Available at: https://digitalcommons.butler.edu/wordways/vol52/iss4/6