If you watched Super Bowl commercials in 2015, you probably remember this one. A woman dials a phone. "911, where is your emergency?" says the voice on the other end.

"I'd like a pizza for delivery," the woman says.

"Ma'am, you've reached 911, this is an emergency line," the dispatcher says.

"A large with half pepperoni, half mushroom."

"Do you have an emergency or not?"

"Yes," the woman says. The camera pans a room in disarray, a hole punched in a wall.

In that chilling moment, it's clear that she knows exactly who she called, that the situation involves domestic violence and that the woman, in earshot of the perpetrator, is in danger.

The powerful ad was created by No More, an organization working to end domestic violence and sexual assault, and sponsored by the NFL. It's based on a real-life 911 call, which the original 911 dispatcher later described in a 2014 Reddit thread.

A team of three Macalester students who were familiar with the ad and share a passion for reducing domestic violence wanted to offer women in that situation a better way to get help.

"How many women are having to go through this struggle — to live with their aggressor and call the police?" said Alessandra Rosa Policarpo, a member of the team.

The students devised a phone application, disguised as a calculator, with features that women could use to call for help and protect themselves without alerting their abusers.

The students created the app as participants in Macathon, an annual Macalester event in which student teams have 24 hours to create an original service or product (a website, an app, a physical item) that solves a real-world problem.

The event begins on a Friday evening in early November, when 18 teams of three to six students go into separate rooms. They brainstorm ideas, do research and create a prototype. Macalester alumni serve as coaches.

After 24 hours, everybody gathers and alumni judges award teams first, second and third place, with cash prizes.

The event "challenges students to make something out of nothing," said Jody Emmings, director of entrepreneurship and innovation, the department that sponsors Macathon. "In that 24-hour period, students put everything else aside to work on their own bold ideas and healing solutions to some of today's most difficult problems."

First place in the 2021 Macathon went to a team that devised an eco-friendly, sustainable packing material for shipping heavy machinery, reducing the volume of single-use material in landfills. Third place went to a team that created an all-natural, non-addictive, stimulating oral spray to help people fight fatigue.

Policarpo and her teammates Jonas Costa and Alice Bruno won second place, with a $750 prize.

They were friends before the event — Policarpo and Costa, both from Brazil, live together and knew Bruno, who is from Italy — but were not allowed to plan anything before Macathon started.

So that Friday evening they began by brainstorming. "On the board were all these topics we care about," Costa said — including immigration, food insecurity, poor women needing menstrual products. Which could they address that weren't already being addressed?

Domestic violence was an issue they all felt passionate about.

"I cannot not care about this," said Costa. The issue "should not be just for women to worry about," he said.

The team surveyed friends around the world — catching people awake in different time zones — gathering reactions. They searched app stores and, although a few apps addressed domestic violence, their features were limited, or their reviews suggested functionality problems. "We wish so hard this app actually worked," one comment said.

Their app opens to an ordinary calculator, but its user could enter a PIN or symbols code to access its functions, which include calling 911 and providing contacts at nearby women's shelters.

The app could also provide a connection to a crisis line; archive photos and recordings that document abuse; and store information about the woman, such as whether she has children, to help shelters better understand her needs.

Macathon is over, but the three plan to keep working to develop their invention (Costa and Bruno are scheduled to graduate in 2023, Policarpo in 2024). Challenges remain, technical and otherwise. For example, how to spread the word about the app among women, without abusers hearing about it. Possibilities include women's social-media groups, or advertisements in women's restrooms. (Some domestic abuse victims are men, but for now the students are focusing on women to make sure the app reaches the right audience.)

"This is something we're not willing to give up on yet," Bruno said.