Ключевые слова: background, billboard, black, black color, blackboard, blank, board, border, chalk, chalk art equipment, chalkboard visual aid, class, classroom, color image, copy space, damaged, design, dirty, drawing, education, empty, frame, grey, grunge, horizontal, illustration, image, isolated, learn, message, no people, old, pattern, retro, retro style, school, scratched, space, square, surface, teaching, texture, textured, vintage, wall, white, wood, wooden, write,