Along the left side of a cold, gray cement building on Alcatraz Island, hundreds of colorful NFL jerseys suspended on clothesline hang limp in the cold air.

The building is about as long as a football field. Broken windows, peeling paint and the busted out remains of what used to be toilets line the walls. It looks like the dirtiest NFL pro shop imaginable, only the jerseys aren’t for sale. They’re art.

“It’s really about shortening irrationally long prison sentences that are too often given for nonviolent minor drug crimes,” says Nelson Saiers, the New York-based artist behind Shortening: Making the Irrational Rational, currently on display on Alcatraz through Sunday, Feb. 5.

The exhibition starts in the corner of the New Industries Building with a giant white “3” on a green piece of synthetic turf suspended from the ceiling. From there, the jerseys wind throughout the building, with the numbers on the back spelling out the first several hundred digits of the number pi.

“Pi is what’s called an irrational number which means it never ends nor repeats,” says the 41-year-old Saiers, who earned a Ph.D. in mathematics at the age of 23 and ran a hedge fund before becoming a full-time artist. “Now the way to turn it into a rational number is to shorten it. So that’s a very good metaphor for what needs to be done to these irrational prison sentences.”

Inspired by news headlines

Saiers’ process began with the news of the death of Freddie Gray, a black man in Baltimore, who died while in police custody in the spring of 2015.

The incident provoked a discussion between Saiers and a friend about the ongoing issues between communities of color and police departments.

“And he said, ‘Well the number one thing they gotta get rid of is football numbers because it’s destroying families,” Saiers says of that conversation. “It’s destroying entire communities.'”

Saiers’ friend told him that “football numbers” referred to double-digit prison sentences.

“It comes from the idea that if you get 30 years or 44 years or 25 years, it’s a number that looks like a number on a football jersey,” Saiers says. “So the football jerseys hanging in the room point to that expression.”

California’s stance on long prison sentences

Many of those double-digit sentences for nonviolent drug crimes date back to tough on crime laws like California’s 1994 “Three Strikes” Law, which established mandatory long prison sentences for repeat offenders.

But those sentences have become less common in recent years. Two recent ballot measures — 2012’s Proposition 36 and 2014’s Proposition 47 — as well as Governor Jerry Brown’s prison realignment plan passed in 2011, were all designed in part to reduce the kinds of long prison terms Saiers protests in his work.

Proposition 36 amended the 1994 Three Strikes Law to establish more lenient sentencing for nonviolent offenders, and Proposition 47 reclassified some nonviolent drug offenses from felonies down to misdemeanors. Both measures included opportunities for offenders already behind bars to appeal and potentially reduce their current sentences. Realignment called for moving some nonviolent offenders, including those with drug convictions, out of state prisons and into county jails.

But even with all of that progress — plus the possibility of even more reduced sentences after the passage last November of Proposition 64 legalizing recreational marijuana — this is not a settled issue.

“While those changes have happened and continue to happen, you will still find people in state prison who are serving long sentences, life sentences,” says Krissi Khokhobashvili, spokeswoman for the California Department of Corrections and Rehabilitation.

The many layers of Shortening

The complexities of Saiers’ artwork go beyond football jerseys and the number pi. For example, the piece also relates to the storied history of Alcatraz.

Saiers repeatedly pays homage in the exhibition to the Native American presence on The Rock. He put duct tape over jerseys emblazoned with the word “Redskins” to “mute” what he sees as a derogatory term. The numbers on those jerseys — 19 and 89 — also reflect the Native American occupation of Alcatraz, where 89 Native Americans held the island for 19 months between Nov. 1969 and Jun. 1971 — an action that helped give birth to the modern Native American civil rights movement.

The work also references famous Alcatraz inmates like Chicago mob boss Al Capone and Robert Stroud (better known as the Birdman of Alcatraz). Saiers says the numbers on the jerseys of bird-related teams (Eagles, Ravens, Seahawks, Cardinals, etc.) add up to 594, which was Stroud’s inmate number at Alcatraz.

In the same vein, most of the Chicago Bears jerseys show number 85, representing Capone, who wore that number while imprisoned on Alcatraz. Saiers says this number 11 jersey with Capone’s name on the back represents the crime boss’ 11-year prison sentence for tax evasion. He says the jersey is smaller than all the others because Capone’s is an example of a sentence that should’ve been lengthened instead of shortened.

Protest art on Alcatraz

Saiers isn’t the first artist to use Alcatraz as a platform to speak out against unfair incarceration.

For example, in 2012, a group of Bay Area artists staged a choreographed dance film at Alcatraz called Well Contested Sites. They were attracted by the site’s complex history of activism and incarceration as well as its physical incongruity as both an old, decrepit prison and one of the world’s most scenic tourist attractions.

“What happens all too often is that these beautiful places become distant places of oppression for certain people,” says Reggie Daniels, one of several artists involved in the film who was previously incarcerated. “So while other people are experiencing the beauty, there are people who are experiencing these dreadful harms and living and suffering with a very harsh quality of life in beautiful spaces like San Francisco.”

Well Contested Sites from Rapt Productions on Vimeo.

Perhaps the most well-known recent example of art activism on Alcatraz was @Large, a 2014-15 exhibition designed by the famous Chinese artist Ai Wei Wei. @Large explored what it means to be free and was seen by nearly 900,000 people during its seven month stay on the island.

“Alcatraz is a place of protest,” says Kate Bickert, who helps run the Golden Gate National Parks Conservancy’s Arts in the Parks program. This program brought Shortening: Making the Irrational Rational to The Rock.

Drawing out the meaning

Beyond historical symbolism, Saiers has a much more practical reason for staging his piece on Alcatraz: The setting helps bring out the meaning in a work that might otherwise seem abstract and impenetrable.

“Having the backdrop be Alcatraz would certainly point people in the direction that this is about prisons,” Saiers says. “Otherwise, you come in and see a room of football jerseys with strange numbers on it and duct tape and things like that, and you may not naturally think about prison sentences.”

Even with the Alcatraz hint, some people still don’t get it. A fair number of visitors do a quick loop through the installation without really stopping. But for some people, like Galen Tom of Fairfield, the unique setting helps the work click into place.

“For me, it really sends a message especially when you don’t get it at first and you think, ‘Oh, I’m in a prison and I’m going through it and these numbers represent people who have served years — some low some high — in drug related offenses,'” Tom says. “It definitely hits at home of understanding and seeing the gloom of the interior of this place.”

For more details about ‘Shortening on Alcatraz,’ see here.