This is a slightly cropped region of a photograph I took at Indianapolis airport in March 2015. It shows a long building with pressurized sodium lights along the front. The cool thing to note are the regions where the traces show strong diagonal patterns to the light and dark dashes. This is due to the fact that the electrical contractor who wired up the lights was fairly rigorous in following a 1 - 2 - 3 - 1 - 2 - 3 sequence when selecting which phase of the three-phase electrical supply each light should be connected to. This is a sensible approach as it balances the load nicely. And, for those who know how to see it, it makes a cool pattern!
