With the exception of palindromes, anagrams are the most difficult kind of word puzzle to compose. The base phrase and the anagram must contain exactly the same letters, and the anagram must be apposite. The criteria for a "perfect" anagram are much stricter still: the anagram must agree in tense and number, precisely describe the base, and contain no filler such as exclamations, unrelated proper names, or irrelevant adjectives.
"An Anagram Composing Contest,"
Word Ways: Vol. 15
, Article 10.
Available at: http://digitalcommons.butler.edu/wordways/vol15/iss4/10