Look down at the yellow bumpy tiles on your train platform. A Japanese man named Seiichi Miyake laid the first ones in Okayama in 1967. With his own money. 230 blocks, right in front of a school for the blind. He had just watched a car nearly hit a blind man at a crossing. A friend told him: even through your shoes, your feet can read the ground. So he built a language you walk on. Today those tiles guide blind people through stations and airports all over the world. Most people never learn his name. Are they on the ground where you live?