Question: What writing principle is relevant in a novel with Allison Gross?

<P0-S0> Allison Gross, a hideous witch, tries to bribe the narrator to be her "leman". <P0-S1>  She combed his hair, first. <P0-S2>  When a scarlet mantle, a silk shirt with pearls, and a golden cup all fail, she blows on a horn three times, making an oath to make him regret it; then she strikes him with a silver wand, turning him into a wyrm (dragon) bound to a tree. <P0-S3>  His sister Maisry came to him to comb his hair. <P0-S4>  One day the Seelie Court came by, and a queen stroked him three times, turning him back into his proper form. <SEP> <P1-S0> Lillia and Treize (リリアとトレイズ , Riria to Toreizu ) is a Japanese light novel adventure series by Keiichi Sigsawa, with illustrations by Kohaku Kuroboshi, starring the children of the characters from "Allison". <P1-S1>  There are six light novels in the series, published by MediaWorks under their "Dengeki Bunko" label. <P1-S2>  The first novel was released on March 10, 2005, and the last novel was published on April 10, 2007; there are three stories in the six volumes, with each story taking up two volumes. <P1-S3>  The series will be followed by "Meg and Seron". <P1-S4>  A manga adaptation by Hiroki Haruse started serialization in the shōjo manga magazine "Comic Sylph" on December 9, 2006, also published by MediaWorks. <P1-S5>  An anime adaptation aired between April and October 2008 based on both the "Allison" and "Lillia and Treize" novels, known as "Allison & Lillia". <SEP> <P2-S0> The rule of three is a writing principle that suggests that events or characters introduced in threes are more humorous, satisfying, or effective in execution of the story and engaging the reader. <P2-S1>  The reader or audience of this form of text is also thereby more likely to remember the information conveyed. <P2-S2>  This is because having three entities combines both brevity and rhythm with having the smallest amount of information to create a pattern. <P2-S3>  It makes the author or speaker appear knowledgeable while being both simple and catchy. <SEP> <P3-S0> Allison (アリソン , Arison ) is a Japanese light novel series by Keiichi Sigsawa, with illustrations by Kouhaku Kuroboshi. <P3-S1>  There are three "Allison" novels, with the third split into two volumes, published by MediaWorks under their "Dengeki Bunko" label. <P3-S2>  The first novel was released on March 10, 2002, and the last novel was published on May 10, 2004. <P3-S3>  There is a follow-up series of light novels called "Lillia and Treize" which were released between March 2005 and April 2007. <P3-S4>  There is also an "Allison" sound novel for the Nintendo DS which was released on December 7, 2006. <P3-S5>  A manga adaptation by Hiroki Haruse started serialization in the shōnen manga magazine "Dengeki Comic Gao! <P3-S6> " on July 27, 2007, also published by MediaWorks. <P3-S7>  The manga ended serialization in "Dengeki Comic Gao!" <P3-S8>  on January 27, 2008, but continued serialization in MediaWorks' seinen manga magazine "Dengeki Daioh" on March 21, 2008. <P3-S9>  An anime adaptation based on both the "Allison" and "Lillia and Treize" novels, known as "Allison & Lillia", aired between April and October 2008.