The solution of difficult word problems seldom comes directly, or all at once. Usually, there is a gradual evolution toward the desired goal. Let us illustrate the process with what has come to be known as the "Jotto" problem.
Borgmann, Dmitri A.
"The "Jotto" Problem,"
Word Ways: Vol. 1
, Article 8.
Available at: http://digitalcommons.butler.edu/wordways/vol1/iss1/8