Quite a different use is made of the pig in Lloyd Alexander's fantasy books "The Chronicles of Prydain", where Hen Wen is a pig with foresight, used to see the future and locate mystical items such as The Black Cauldron. One of the earliest literary references is Heraclitus, who speaks of the preference pigs have for mud over clean water in the "Fragments". In Wu Cheng'en's 16th century Chinese novel "Journey to the West", Zhu Bajie is part human, part pig. In books, poems and cartoons in 18th century England, The Learned Pig was a trained animal who appeared to be able to answer questions. Thomas Hardy describes the killing of a pig in his 1895 novel "Jude the Obscure". Pigs have featured in children's books since at least 1840, when "Three Little Pigs" appeared in print; the story has appeared in many different versions such as Disney's 1933 film and Roald Dahl's 1982 "Revolting Rhymes". Even earlier is the popular 18th-century English nursery rhyme and fingerplay, "This Little Piggy", frequently in film and literature, such as the Warner Brothers cartoons "A Tale of Two Kitties" (1942) and "A Hare Grows In Manhattan" (1947) which use the rhyme to comic effect. Two of Beatrix Potter's "little books", "The Tale of Pigling Bland" (1913) and "The Tale of Little Pig Robinson" (1930), feature the adventures of pigs dressed as people. Several animated cartoon series have included pigs as prominent characters. One of the earliest pigs in cartoon was the gluttonous "Piggy", who appeared in four Warner Brothers "Merrie Melodies" shorts between 1931 and 1937, most notably "Pigs Is Pigs", and was followed by Porky Pig, with similar habits. Piglet is Pooh's constant companion in A. A. Milne's Winnie the Pooh stories and the Disney films based on them, while in "Charlotte's Web", the central character Wilbur is a pig who formed a relationship with a spider named Charlotte. The 1995 film "Babe" humorously portrayed a pig who wanted to be a herding dog, based on the character in Dick King-Smith's 1983 novel "The Sheep Pig". Among new takes on the classic "Three Little Pigs" is Corey Rosen Schwartz and Dan Santat's 2012 "The Three Ninja Pigs". Pigs have appeared in art in media including pottery, sculpture, metalwork, engravings, oil paintings, watercolour, and stained glass, from neolithic times onwards.