Marx Brothers "The Cocoanuts" (1925–1926) and "Animal Crackers" (1928–1929). Playwright George S. Kaufman worked on the last two and helped sharpen the brothers' characterizations. Out of their distinctive costumes, the brothers looked alike, even down to their receding hairlines. Zeppo could pass for a younger Groucho, and played the role of his son in "Horse Feathers". A scene in "Duck Soup" finds Groucho, Harpo, and Chico all appearing in the famous greasepaint eyebrows, mustache, and round glasses while wearing nightcaps. The three are indistinguishable, enabling them to carry off the "mirror scene" perfectly. The stage names of the brothers (except Zeppo) were
Karl Marx and the Close of His System their "positivist narrowness". The Marxist economist Paul Sweezy rejects Bawerk's view that the theory of value must be abandoned. However, he considers "Karl Marx and the Close of His System" to be the best statement of the argument that the fact that the law of value is not directly controlling in capitalist production requires the rejection of the theory of value. Karl Marx and the Close of His System Karl Marx and the Close of His System () is a critique of Karl Marx's economic theories by the Austrian economist Eugen Böhm von Bawerk, published in English translation in 1898.