The NaviLens system has been spreading across Barcelona’s transit system during the last few months with pixelated stickers. Each is a 5×5 stack of brightly colored squares on a black card.
Across the city’s network of buses, trains, and trams traveling up the steep hillside of Montjuïc, the tags are stuck near exits, platforms, escalators, ticket booths, intercoms, and passageways.
This is a program by Transports Metropolitans de Barcelona (TMB), the public transport service, to make the city easier to access and navigate for its thousands of visually impaired citizens.