Thirteen is an unlucky number. Mirrors smash in its presence, black cats dart under ladders for safety, and witch's pour a cocktail of salt and rabbits' feet into opened umbrellas. Thirteen million, on the other hand, is a very lucky number, especially if you're a member of Mojang. Ultra-phenome-megagame Minecraft has now exceeded that number in PC sales. That's - as of writing - 13,000,447 people who have punched a cube tree with their cube fist.