I was rather hoping for the practical experiment. Those I did 20 years ago were first done in a meadow and then in a newly laid bitumen car park. We laid out the MY rod 40 times and ne'er got a single agreement. If I recall a few inches were involved when using wooden rods on a reasonably flat surface. We assumed that over greater distances a few inches could easily extend to a few feet, especially if precautions were not taken to measure in a straight line.

In theory it seemed like the experiment would prove us wrong but it's only the hands-on approach that matters. Besides, there are better ways to go about consistently laying down pre-determined measure with some accuracy and it ain't with ropes or rope knots.

Graham