According to Graham, Ulm's work analyzes cities "the way you’d analyze a material, looking at factors such as the arrangement of buildings, each building’s center of mass, and how they’re ordered around each other." Some of Ulm's conclusions: "Boston’s structure, for example, looks a lot like an 'amorphous liquid.' Seattle is another liquid, and so is Los Angeles. Chicago, which was designed on a grid, looks like glass, he says; New York resembles a highly ordered crystal."
"If the analogy does hold up, Ulm hopes it will give planners a new tool to understand a city’s structure, its energy use, and possibly even its resilience to climate change."
Graham's article includes Ulm's work among the inroads made by researchers in the "science of cities" by quoting Michael Mehaffy, who wrote on that subject for Planetizen in June. Mehaffy's take on Ulm's work: although it's "fascinating and potentially very important," but that comparisons can be reductive of the unique structures of cities.