I don’t suspect that many of you have ever flown at relatively low altitudes over the state of Iowa. I used to do it fairly regularly, flying by turbo-prop jet from Minneapolis to Sioux City. One of the incredible things that you see (okay, maybe the only incredible thing you see) looking out the plane window as you pass over Iowa is that, more or less, the entire state of Iowa, all 56,272 sq mi sqare miles of it, is criss-crossed by gravel roads exactly one square mile in area.
Check out this google maps image. This is just a random part of Iowa that I picked out. Scroll around. Nothing but squares.