what are the color combinations in mtg?
['White + Blue = Azorius.', 'Blue + Black = Dimir.', 'Black + Red = Rakdos.', 'Red + Green = Gruul.', 'Green + White = Selesnya.', 'White + Black = Orzhov.', 'Blue + Red = Izzet.', 'Black + Green = Golgari.']