After a diverted journey – police had closed the road I had intended to use – I had to choose a different route. I had to ignore the satnav: it just wanted me to go back and use the blocked road. So I followed a guessed route on roads I had never travelled before.
The surprise was that the journey took only 225 miles compared with the ‘normal’ 219 miles. Only six miles added in spite of the fact that my journey went a good thirty miles to one side of my ideal track.
It always surprises me how a tiny addition to the length of a piece of taut string turns it into a slack string with a huge range of possible positions. (Try it.) The shortest track is not available to us non-crows, but it seems that most ‘not-quite-shortest-tracks’ are of very similar lengths.