A man who copied other people's words for a living bought a strange book for two coins. It was not paper or parchment. It was made of the bark of young trees. The cover was brass. The letters were in a language he did not know. He spent the rest of his life trying to understand it. He painted its diagrams on his walls. He showed them to everyone who visited. Nobody could read them. He walked for years looking for someone who could. He found one man in Spain. The man died on the way home. But by then the copyist had understood the principle. He and his wife worked for three more years. Then they made gold. They built fourteen houses for the poor. They repaired seven churches. They asked for nothing. The book cost him two coins. Everything else it cost him was his life.