Ключевые слова: background, blue, building, business, circle, clock, cog, cogwheel, college, concept, connection, construction, cooperation, education, engine, engineering, equipment, face, gear, heavy, illustration, industrial, industry, knowledge, machine, machinery, man, manufacturing, mechanical, mechanism, metal, motion, movement, one, part, person, plant, power, rotation, school, steel, student, teamwork, technical, technology, transmission, university, wheel, work, working,