Ключевые слова: art, book, chemistry, class, collection, college, concept, contour, design, education, element, explaining, geography, graduation, graphic, hat, icon, illustration, intelligence, isolated, knowledge, learning, line, linear, logo, math, monochrome, outline, owl, reading, research, ring, school, science, set, sign, silhouette, studying, subject, symbol, teaching, thin, university, webinar,