It's a huge 3D-printed map of Manhattan wired up to optic fiber cables. The cables show lights where each subway train is, and a Raspberry Pi sits at the heart to grab the location data.

The concept is simple, but executed brilliantly. In the summer of 2009, ... handing out self-addressed stamped cards that were letter pressed with an outline map of Manhattan.

Rivera became Manhattan’s map guy by accident. He started as an intern in 1994 under Borough President Ruth Messinger, making photocopies of speeches and agendas. In 2008, ...