The theorem of Pappus is a result from projective geometry about nine points and nine lines. It can be used as a basis for a word game similar to the game of David Silvermann using the word stockpile ARMY CHAT FISH GIRL HORN KNIT SOUP SWAN VOTE (A. Ross Eckler, "Word Recreations" (Dover Publications, 1979), p. 113).
Farrell, Jeremiah and Wright, David
"Pygmalion: A Pappus Word Game,"
Word Ways: Vol. 25
, Article 5.
Available at: http://digitalcommons.butler.edu/wordways/vol25/iss4/5