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Penguins: the emperors of fluid dynamics
Sam Harris looks at how Pingu and his friends can stay cosy
Chalkdust issue 11 puzzle hunt #2
TD Dang sets the second puzzle. Can you solve it?
Christmaths carols II
Behind today's door... Another carol!
The joys of the Jacobian
Robert Smith? tells us how his favourite matrix saves lives
Roots: All things being equal
The story of how we got the equals sign
Why is it so hard to pull two phone books apart?
Take two phone books and interleave all their pages one by one. Now try and pull them apart by their spines. Impossible, right?