Monthly Archives: January 2014

Cipher 54: Zero-sum game

Alice and Bob have been playing a zero-sum game; their moves are tabulated below: Good luck.

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Solitons and trains

Suppose we have a circular track occupied by finitely many trains of various lengths travelling at the same speed. The trains collide elastically with each other. If the sum of the lengths of the trains is a rational multiple of … Continue reading

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Cipher 53: Multicoloured

Some exciting things have happened recently. Amongst them, it has been proved that combinatorial designs (generalised Steiner systems) exist for all tuples of parameters for which a necessary divisibility criterion is satisfied. Anyway, the cipher:

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Descartes snark

As I’ve mentioned before, a snark is a 3-regular bridgeless graph which cannot have its edges 3-coloured such that each vertex is incident with one edge of each colour. One particular example is curiously named the Descartes snark, and is … Continue reading

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Cipher 52: Tetragrammaton

Here’s the second cipher for this year. Determine the missing symbols to obtain the password:

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Complications of furniturial locomotion

My favourite author, after whom I was named, is undoubtedly Douglas Adams. I particularly enjoyed Dirk Gently’s Holistic Detective Agency (sadly, not quite as famous as his bestseller, The Hitchhiker’s Guide To The Galaxy), featuring a rather disorganised and slightly … Continue reading

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Cipher 51: Wild bee chase

To mark the beginning of 2014, the third season of ciphers has now commenced. This one should be reasonably fun to solve: It’s a multi-step puzzle, but you should know once you’ve solved each step.

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Quite a while ago in the Eagle pub in Cambridge, James Watson and Francis Crick announced the double-helix structure of DNA. This discovery was based on earlier X-ray diffraction experiments by Rosalind Franklin. In eukaryotic organisms such as ourselves, DNA has a linear … Continue reading

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