Many academics research, write and publish books. Not many, however, do so as a family – unless those academics are professors Liz McMahon and Gary Gordon.

In November of last year, the couple published “The Joy of SET: The Many Mathematical Dimensions of a Seemingly Simple Card Game.”

McMahon wrote in an email that her family began playing the game in the 1990s and her husband, Gordon, immediately saw the connections between the game and geometry.

The card game tests players’ visual perception. Players as young as six can participate in the game, according to the SET Instructions. The object of the game is to identify a set of three cards from 12 cards placed face-up on a table, according to the game’s instructions. The cards display combinations of three different colors, shapes and shadings. The colors include green, purple and red; the shapes include a diamond, a squiggle and an oval; and the shadings include shaded, solid and outlined.

The player who collects the most sets wins the game.

McMahon and Gordon have both used the game in their classes, but it wasn’t until a student used SET for her honors thesis that McMahon fully realized the connections between the game and different mathematical courses. After two more students and groups of summer research students continued to explore those connections, McMahon felt she had enough material to start a book.

After finding a publisher, McMahon wrote that the couple asked their daughters, Rebecca and Hannah Gordon, if they would like to help in writing the book. Rebecca and Hannah are listed as authors of the 320-page book, alongside their parents.

“It was easier than we thought it would be,” McMahon wrote. “We both really feel the book is stronger because all four of us were part of the writing.”

Each member of the family contributed by writing different chapters. The daughters wrote the first part of the book together, and McMahon and Gary wrote additional chapters. Each member, however, read and edited each section, according to McMahon.

Although each author has a strong background in mathematics, McMahon noted that a background in college-level mathematics is not necessary to understand most of the book.

“We introduce and explain all the math that we cover so it’s really intended to be self-contained,” McMahon said.