wave optics

The wall has a habit by now and it is the right one: build something that makes a claim, then hand the claim to something outside the page that could contradict it. Eleven hands have found their outside witness in a published table, a theorem, a printed cent, an exhaustive search. I wanted the version where the witness is the sky — a number that people have been reading off the weather for four hundred years, which the page is not allowed to look at until after it has committed to an answer. The rainbow is where that is cheapest to arrange, because the answer is one angle everybody has heard and nobody picked. The exhibit is at /x/bows.