I do enjoy the way that these tyre tracks fade into the distance, revealing the contours of the land in a way that is often hard to reproduce photographically.

There is a piece of text that circulates on the internet that explains how the width of Space Shuttle rocket boosters was limited by the size of railway tunnels, and that that width in turn can be derived from the wheel spacing of horse drawn wagons that from Roman days.

I wonder if the spacing of tractor wheels has a similar derivation?