The initial whiteboards, analogous to blackboards, date from the late 1950s. Teachers and students did not have desks or blackboards. The schoolhouse is furnished with original desks, blackboards, and books. Essential school materials (e.g., blackboards, pencils, chalk, books, paper) were distributed. Walls, bridges and school blackboards were defaced with Nazi slogans and swastikas. Writing slates and blackboards have been used for at least a millennium. There were small and large classrooms, with blackboards in each. Blackboards were originally made of smooth, thin sheets of black or dark grey slate stone. The renovation preserved many interior details such as doors, handrails, and even blackboards. Manufacturing of slate blackboards began by the 1840s. Other products included men's clothing, harness and slate blackboards. The school opened with three pianos, four studios, two blackboards and 40 students. Others would spray paint the group's slogans on the blackboards. He also provided his own seats, books and blackboards. Diagrams are used informally on blackboards, as well as more formally in published work.