Ключевые слова: and, apparatus, black, close, close up, cog, cogwheel, connection, cooperation, corrosion, electric motor, engine, engineering, equipment, factory, gear, gearing, gray, grinding, group of objects, industrial equipment, industry, interlocked, iron, large, machine, machine teeth, machinery, manufacturing, mechanical, mechanics, mechanism, metal, monochrome, old, pinion, power, precision, progress, shiny, steel, surface, teamwork, technology, togetherness, tool, transmission, up, wheel, work,