Anne and Gilbert comprise a dynamic pair of foils in Anne of Green Gables. At the beginning of the novel, Anne is the protagonist and Gilbert is the antagonist. Anne is the outsider (an orphan), and Gilbert is an insider (a native of Avonlea). And most importantly, Gilbert wants to be friends, but Anne initially refuses because of an incident in Chapter 15 when he teases her about having red hair:
Gilbert reached across the aisle, picked up the end of Anne’s long red braid, held it out at arm’s length and said in a piercing whisper: “Carrots! Carrots!”
Here, Gilbert makes Anne feel like an outsider by making fun of her hair in front of an entire class. He calls her braids "carrots" to remind her of their strange color. She responds by refusing to attend school or acknowledge Gilbert's existence. However, by the end of the novel, Anne and Gilbert learn to look beyond their differences and become good friends. Gilbert's sacrifice of his teaching position at Avonlea becomes a catalyst for their friendship.
This interesting pair of foils evolves from protagonist and antagonist into a pair of good friends. This develops the novel as a bildungsroman and underscores the idea that people can change and grow into mature adults. Despite the fact that Gilbert embarrassed Anne early on in the story, he manages to win her back with an act of selflessness. They later become more than friends: Anne of Green Gables is the first of many books in a series in which Anne and Gilbert eventually get married. By making them foil characters in the first book, Montgomery cultivates the reader's interest in their story and heightens the emotional contrast between their initial encounter and their eventual fate.
Matthew and Marilla are foils for each other, particularly in the way they treat Anne. Marilla wants to raise Anne in a very strict and religious manner, whereas Matthew is indulgent, affirming, and full of praise. He advocates for Anne to stay at Green Gables and always strives to understand her fanciful imagination. He also buys Anne her dream dress in Chapter 25 (titled "Matthew Insists on Puffed Sleeves"):
Probably some wise, inscrutable motive was to be served [by not buying the dress]. But surely it would do no harm to let the child have one pretty dress—something like Diana Barry always wore. Matthew decided that he would give her one [...] A nice new dress would be the very thing for a present. Matthew, with a sigh of satisfaction, put away his pipe and went to bed, while Marilla opened all the doors and aired the house.
In a previous scene, Marilla had expressed disapproval of puffed sleeves and instead made three conservative dresses for Anne. But Matthew sees "no harm" in letting Anne wear a dress with puffed sleeves. He goes all the way to Carmody to buy it, and, crippled by awkwardness, purchases 20 pounds of sugar instead. He then decides that he needs a friend's assistance and asks Mrs. Lynde to buy and sew the dress. The great lengths to which he goes demonstrate his commitment to improving Anne's life.
By contrast, Marilla is strict and sarcastic and requires Anne to do many chores. Given that Anne is "old enough to be of some use in doing chores right off and young enough to be trained up proper," Marilla believes that she can successfully train Anne to be a helpful and moral member of Green Gables. She also prioritizes religion and makes sure that Anne learns the Lord's Prayer rather than going out into nature and "feel[ing] a prayer" as Anne is accustomed to doing. Anne sometimes feels stifled by Marilla's moralizing, but the two manage to eke out a grudging friendship that blossoms into mutual respect when Anne matures into a young adult. Matthew and Marilla create a balanced upbringing for Anne, who might have become too spoiled or too bitter under just one of their methods. This pair of foil characters also gives the story emotional texture by creating a pattern of disagreement, resolution, and evolution throughout the story.
