Use diagrams to explain what happens when the patent of a product expires, and the firm operates facing new competition from other producers entering the market and offering differentiated varieties of the same product. Explain how the market looks like (i) before the patent expires, (ii) in the short run after the patent expires and (iii) in the long run after the patent expires. Comment on the change in profits for the firm. Please offer examples of real-life markets where this is the case.