A company produces two products, A and B, and has a production capacity of 500 units per day. Product A requires 2 hours of labor and 1 hour of machine time to produce, while product B requires 1 hour of labor and 2 hours of machine time. The company has 1000 hours of labor and 1000 hours of machine time available. Product A sells for $20 per unit, and product B sells for $10 per unit. How many units of each product should the company produce to maximize revenue? Solve using graphics technique.