The avout's only media are chalk, ink, and stone. They chose those three on purpose, for what each one does to a mind. Chalk fades, so you rewrite and rethink. Ink commits you to the page. Stone outlives you, so you only carve what deserves to last. Every medium trains its user. They made the choice deliberately. Most people just inherit whatever is newest and let it train them by accident. Ripped from the novel: "Living as we do under the Cartasian Discipline, our only media are chalk, ink, and stone,"

— In our words · Source: Anathem (Neal Stephenson)