Ключевые слова: 20, 80, analysis, background, black, blocks, business, composition, concept, conceptual, cubes, dark, design, economic, education, efficiency, effort, eighty, factor, few, flat, grey, law, lay, management, many, metaphor, nobody, object, pareto, percentage, percents, presentation, principle, productivity, proportion, result, rule, sparsity, top, twenty, view, vital, wooden,