The Economist reviews the new 3D movie “Arthur Christmas”:

The screenplay, written by Aardman’s Peter Baynham and Sarah Smith, makes a serious stab at the mathematics. Some 23% of the world’s seven billion people were assumed to be under age eight—which is probably not far off the mark. So, with 1m elves working in teams of three, each team rappelling down ropes from Santa’s hovering stealth-ship has to deliver presents to 4,760 children during the 24 hours of Christmas Eve. Hence the 18 seconds or so the movie allows for each stocking to be filled.