Ключевые слова: abstract, arrow, art, background, city, clip art, colorful, concept, connections, cover, creative, curves, design, diagram, element, generic, graphic, guide, illustration, infographic, knot, line, many, map, metro, modern, net, network, opposit, ornament, outline, pattern, perspective, plan, railway, scheme, shape, station, stylish, subway, transport, transportation, travel, tube, underground, urban, wallpaper,