At the Joint Mathematics Meeting, Dr. Mark Branson and his research students, Robert Chen (top picture) and Malik Naanaa, presented their research on the geometry of Baltimore's public transportation system during the Freddie Gray protests last year . During last summer, they built a model of the city's transit system on a normal day and on the day of the protests, and used that model to analyze how the geometry changed.  Then they presented their work this January at the conference in Seattle, Washington.