Six Impossible Things: Issue 2

March 17, 2024. In the first issue of 6IT: the mathematics of supervising children; unreliably clairvoyant demons; why the sky is blue (and why it isn’t); a Poisson process for primes; sychronizing fireflies; and quantum error correction from Penrose tilings.

β€œThere's no use trying, ” she said. β€œOne can't believe impossible things.” β€œI daresay you haven't had much practice,” said the Queen. β€œWhen I was your age, I always did it for half-an-hour a day. Why, sometimes I've believed as many as six impossible things before breakfast.”
β€” Lewis Carroll, Through the Looking Glass

Inspired by one of my heroes, John Baez, I’m planning to blog about β€œfinds” in the hard sciences on a semi-regular basis. These may be papers, favourite theorems, new discoveries, or shower thoughts; I’m hoping to be brief and nerdily enthusiastic rather than thorough and technically deep. Either way, I hope it’s fun to read. Let’s see how it goes!


  1. The obstructed supervision theorem
  2. Zermelo’s demon and the axiom of choice
  3. Why the sky is blue
  4. A game of primes
  5. The firefly effect
  6. Quantum error correction from Penrose tilings

1. The obstructed supervision theorem