A Tale of Two Auto Plants - WSJ

What does the article imply about the relationship between GM's and Toyota's production functions and the relationship between GM's and Toyota's marginal product curves, based on the current productivity rating reported by Harbour Consulting (p.1 of article)? Graph GM's production function and Toyota's production function, clearly illustrating their relative shape. Graph GM's marginal product curve and Toyota's marginal product curve, clearly illustrating their relative shape.