Braille is written communication for blind people. It is represented by embossed material either in paper or plastic (on public signs), etc. It is an information visualization alternative for people who communicate differently. For people who view it visually can also take away information from it as it represents alphabetical letters. In addition to be an informative representation, it is also a physical representation that can be felt, and is thus a perfect merger of visual as well as physical.

Source: https://gizmodo.com/how-braille-was-invented-1471756840