The website names.911memorial.org allows you to search for a person or group on the memorial by name, birthplace, job, first responder unit, or flight. The search results show a picture of the correct panel, as well as the panel's number. The number corresponds to a map that allows visitors to easily locate the name.

The names algorithm works in two stages. The first stage, really an algorithm unto itself, builds clusters of names from the adjacency requests. If person A needs to be near person B, and person B near person C, those three names will form a cluster. "That kind of results in a pile of really irregularly shaped puzzle pieces," Thorp says. Among the various indivisible bunches formed by the clustering algorithm were blocks with as many as 70-odd names.

A second, space-filling algorithm takes those puzzle pieces and fits them into place within the confines of the 76 bronze panels enclosing each memorial pool. [See below for a NOVA video about the fabrication and etching of the panels.] "In general it takes the big pieces and finds a place for them, and then fills in the gaps with the small pieces," Thorp explains. He says it took about a month to get the algorithms working, followed by months of tweaks as design requirements shifted.

The 9/11 Memorial will cluster people together who share bonds through friendship, work or incredible story. In the end, it's an algorithm created to have an emotional impact. It gives the names on the wall a story. If you have a loved one who passed away during 9/11, you can find his or her name on the memorial here.

On that terrible morning, when American Airlines Flight 11 hit the North Tower of the World Trade Center, Victor Wald, 50, was working in his 84th floor office at the small brokerage firm, Avalon Partners. Like his colleagues, he raced for the exits, and scrambled down the stairs. But, having suffered from rheumatic fever as a child, he collapsed in exhaustion on the 53rd floor, as frantic workers from the building's upper floors hastily passed him by. Harry Ramos, 46, the head trader at the small investment bank, May Davis Group, who worked on the 87th floor, saw him on the stairs, and stopped.

They had never met, had no friends or relatives in common. But Ramos saw Wald and said, "I won't leave you." Ramos managed to coax Wald down to the 36th floor, where they sat together as the building collapsed.

When the National September 11 Memorial opens this fall, on the tenth anniversary of that world-changing day, the two friends’ names will be inscribed next to each other on the granite wall surrounding the Memorial Garden’s fountains.

To help figure out how the names would be arranged, museum and public space media design firm Local Projects was brought on.

9/11 Memorial Names An artist rendering of the 9/11 Memorial by Squared Design Lab. Image courtesy of the National September 11 Memorial & Museum.

"The architect and the Memorial had decided on this arrangement schema as a design move to try keep all the names undifferentiated," said Jake Barton, director of Local Projects. "They wanted to make a latticework of meaning underneath all those names. You have families clustered together, best friends, even incredible stories of strangers who died on that day, all of which was identified through this process to create meaningful adjacency."

In 2009/2010 I worked with Jake Barton and Local Projects - localprojects.net - to develop a tool for placing the victims names on the 9/11 Memorial in New York City.

The tool works with layouts generated through a custom algorithm I created to satisfy the adjacency requests made by next-of-kin.

Overall there were 18 panels per side plus one corner for a total of 76 panels. The placement of the names also reflects which tower the people were in. The names of those who’s lives were lost in the 1993 World Trade Center bombing, as well as first responders and airplane passengers are present as well. in the end, 98% of the requests were able to be fulfilled. As Thorp stresses on the blog, the use of algorithms to design the layout is largely invisible from the final product. Instead the names of victims is foregrounded above all. Each of the names is given the same amount space and weight so that they are all perceived as being equal.

This post has been a technical documentation of a very challenging project. Of course, on a emotional level, the project was also incredibly demanding. I was very aware throughout the process that the names that I was working with were the names of fathers and sons, mothers, daughters, best friends, and lovers.

Lawrence Davidson. Theresa Munson. Muhammadou Jawara. Nobuhiro Hayatsu. Hernando Salas. Mary Trentini.

In the days and months that I worked on the arrangement algorithm and the placement tool, I found myself frequently speaking these names out loud. Though I didn’t personally know anyone who was killed that day, I would come to feel a connection to each of them.

This project was a very real reminder that information carries weight. While names of the dead may be the heaviest data of all, almost every number or word we work with bears some link to a significant piece of the real world. It’s easy to download a data set – census information, earthquake records, homelessness figures - and forget that the numbers represent real lives. As designers, artists, and researchers, we always need to consider the true source of data, and the moral responsibility which they carry.

One name was misspelled on the 9/11 memorial.

Not even a complicated computer algorithm is always accurate. The program that arranged the 2,983 names inscribed on the 9/11 memorial where the World Trade Center once stood got one name wrong, misspelling Jeffrey Schreier as “Jeffery.”

Don’t blame the computer though: it was likely the result of a human incorrectly entering the data. So far, the misspelled name is the only error on the memorial.

Schreier’s remains were never recovered from the wreckage of the trade center and his family told NBC New York that they hoped the memorial would serve as peaceful place of remembrance. Instead, it was distressing to see the mistake.