Ключевые слова: aad, abbreviation, acromym, acronym, background, billboard, black, blackboard, board, chalk, chalkboard, color, concept, copy, copyspace, definition, dirty, drawing, education, erase, grunge, handwriting, knowledge, learn, learning, lecture, lesson, letter, message, nobody, old, phrase, scratch, space, study, studying, symbol, teaching, text, texture, training, used, white, wooden, word, write,