Graphic aids is a combination of graphic and pictorial material designed for the orderly and logical visualizing of relationships between key facts and ideas, e.g. comparisons, relative amounts developments, processes, classification or organization. Important to the teaching-learning process are the following graphic aids as display boards, charts (diagram, maps, posters, graphs, etc.), cartoons, and comic strips. A chalkboard or blackboard is a reusable writing surface on which text or drawings are made with chalk or other erasable markers. Blackboards were originally made of smooth, thin sheets of black or dark gray slate stone. Modern versions are often green or brown and are thus sometimes called a green board or brownboard instead. Flannel board is sometimes called a flannel graph. This teaching tool is called by different names. Visual board, frick board, slap board, felt board, coherograph, video graph, flannel graph is a storytelling system that uses a board covered with flannel fabric, usually resting on an easel. Peg board is a type of board, which contains small holes to fix certain letters into the holes, and is used especially in the offices to display certain items, name of the personal or faculty member.