Ключевые слова: backgrounds, built structure, business finance and industry, circle, construction industry, design, ditch, drain, drainage, duct, equipment, hong kong, horizontal, housing development, improvement, industry, material, new, occupation, pattern, people, pipe tube, pipeline, plastic, plumber, pvc, repairing, residential district, retail place, scale, service, sewage, social issues, storage room, textured, tube, tubing, water, water pipe, white color,