The number 3 is a very mystical and spiritual number featured in many folktales (three wishes, three guesses, three little pigs, three bears, three billy goats gruff). In ancient Babylon the three primary gods were Anu , Bel ( Baal ), and Ea , representing Heaven, Earth, and the Abyss. Similarly, there were three aspects to the Egyptian sun god: Khepri (rising), Re (midday), and Atum (setting). In Christianity there is the Trinity of God the Father, God the Son, and God the Holy Spirit . Plato saw 3 as being symbolic of the triangle , the simplest spatial shape, and considered the world to have been built from triangles. In German folklore a paper triangle with a cross in each corner and a prayer in the middle was thought to act as protection against gout, as well as protecting a cradle from witches. Three black animals were often sacrificed when attempting to conjure up demons. On the other hand, a three-coloured cat was a protective spirit. In William Shakespeare ’s Macbeth (1606–07) there are three witches, and their spell begins, “Thrice the brindled cat hath mewed,” reflecting such superstitions. Also, 3 is the dimension of the smallest magic square in which every row, column, and diagonal sums to 15.