By Alexa Aguilar Chicago Tribune CHICAGO — Allie Hays’ friends had a good laugh when they heard about the class she had signed up for at North Central College in Naperville, Ill.: Mathematics of Square Dancing. Hays thought it was pretty funny herself at first. “I said, ‘Are you kidding me? That’s a reach,”‘ said the senior math major.

But after spending three hours a day for two weeks memorizing almost 100 dance “calls,” then weaving in and out of complicated formations on cue, she has changed her mind. Amid constant movement, she has had to visualize and use math concepts like shapes and patterns, group theory, fractions and permutations.

“It’s math in motion — you’re walking through mathematics and would have no idea you’re working with concepts that most college math majors don’t study until their fourth year,” says math professor David Schmitz, describing square dancing as “solving a Rubik’s Cube.” Saundra Bryant, a Chicago caller — the person who stands and sings or speaks rapid-fire calls, or dance cues — tested students’ knowledge with a simulated dance Thursday.

Disregarding traditional square-dance tunes, she typically sets her calls to everything from disco to Frank Sinatra to hip-hop. As she crooned the lyrics of Van Morrison’s “Moondance,” she laid out the series of calls. Concentrating, the eight students stepped through the moves. Occasionally, Bryant stopped them to see if they could identify which dancers were the apex of a triangle or how many diamond shapes were in one formation.