Something does not add up
The great Scottish comedian Hector Nicol used to tell a joke about a signalman in the Highlands who applied for a promotion and had to sit a test. This consisted of ever more outlandish scenarios about what he would do if two trains were running towards each other on the same line of track while a series of disasters befell his signalling equipment. The punchline of the joke, after his signal box had caught fire, the points had been jammed…