Ключевые слова: abstract, art, backdrop, background, billboard, black, blackboard, blank, board, chalk, chalkboard, class, classroom, college, concept, copy, dark, design, detail, dirty, drawing, dust, education, element, empty, frame, grunge, horizontal, isolated, lesson, messy, old, pattern, random, realistic, retro, rubbed, school, sign, smudge, space, stain, surface, texture, textured, university, vintage, wall, white, write,