Roald Dahl on 13 September is celebrated as "Roald Dahl Day" in Africa, the United Kingdom and Latin America. In honour of Dahl, the Royal Gibraltar Post Office issued a set of four stamps in 2010 featuring Quentin Blake's original illustrations for four of the children's books written by Dahl during his long career; "The BFG", "The Twits", "Charlie and the Chocolate Factory", and "Matilda". A set of six stamps was issued by Royal Mail in 2012, featuring Blake's illustrations for "Charlie and the Chocolate Factory", "The Twits", "The Witches", "Matilda", "Fantastic Mr Fox", and "James and the Giant Peach". Dahl's influence
The Cat in the Hat circumstances" which is soon enhanced by make believe. The book starts in a factual, realistic world, which crosses over into the world of make believe with the loud bump that heralds the arrival of the Cat. However, this is the first Dr. Seuss book in which the fantasy characters, i.e. the Cat and his companions, are not products of the children's imagination. It also differs from previous books in that Sally and her brother actively participate in the fantasy world; they also have a changed opinion of the Cat and his world by the story's end. Ruth MacDonald asserts, ""The