How does Santa manage to squeeze through chimneys? How do reindeers manage to fly? When will I get the Christmas shopping done? These things are mysteries, so in keeping with the mood, Door 8 opens on some of our favourite mysteries from the world of maths.

Forget the shopping and join us in musing over Achilles and the tortoise, exotic geometries, the paradoxical barber and whether being nice to others is just for Christmas, or a good survival strategy.

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