If we forget money and measure everything in ‘hours of necessary work’, we can see how profit is generated. If the cost of putting Nazma at the factory gate six days a week is thirty hours work by other people spread across the whole of society (to produce her food, clothing, energy, childcare, housing and so on), and she then works sixty hours a week, her work is providing double the amount of output for the inputs. All the upside goes to the employer.