restrictions. In the earliest known occurrence of this problem, in the medieval manuscript Propositiones ad Acuendos Juvenes, the three objects are a wolf, a goat, and a cabbage, but other cosmetic variations of the puzzle also exist, such as: wolf, sheep, and cabbage;, p. 26 fox, chicken, and grain; fox, goose and corn; and panther, pig, and porridge. The logic of the puzzle, in which there are three objects, A, B, and C, such that neither A and B nor B and C can be left together, remains the same. Another version of the puzzle stemming from a Chinese legend is recorded in an 18th-century painted panel by Japanese artist Maruyama Ōkyo, in the collection of the British museum. According to the legend, when a tiger has three cubs, one of them will be a leopard rather than a tiger, and more fierce than the others. Following this legend, the subject of a tiger with her cubs became a traditional subject for art in east Asia. The depiction by Ōkyo shows the tiger family crossing a river, with the mother carrying one cub across the river at a time. This depicts a puzzle equivalent to the puzzle of the wolf, goat, and cabbage, asking how the mother can do this without leaving the leopard cub alone with any of the other tiger cubs. The same variation of the puzzle has also been recorded as a koan of Ryōan-ji, a Zen temple in Kyoto. The puzzle has been found in the folklore of African-Americans, Cameroon, the Cape Verde Islands, Denmark, Ethiopia, Ghana, Italy, Romania, Russia, Scotland, the Sudan, Uganda, Zambia, and Zimbabwe., pp. 26–27; It has been given the index number H506.3 in Stith Thompson's motif index of folk literature, and is ATU 1579 in the Aarne–Thompson classification system. The puzzle was a favorite of Lewis Carroll, and has been reprinted in various collections of recreational mathematics., p. 26. In his 'Arabian Nights' memoir, Meetings with Remarkable Men, the metaphysical Magus, G. I. Gurdjieff cites this riddle as "The Wolf, the goat and the cabbage". He notes, "This popular riddle clearly shows that...not solely by means of the ingenuity which every normal man should have, but that in addition he must not be lazy nor spare his strength, but must cross the river extra times for the attainment of his aim." Variations of the puzzle also appear in the adventure game