October 25th – Although it was lightly raining, it was warm, and with the wind behind me I took the back way back to Brownhills, down the Lichfield Road and up over Springhill at Barracks Lane. 

I had a play with long exposure shots at Sandhills, and was quite pleased with the result, but puzzled too, when I looked at the images on the computer. In both, a wavy, oscillating thin trace of light is present above the main vehicle trails, which are very straight. I thought about these thin, curling traces for almost an hour, then I worked them out. 

They’re the light trail created by the reflection of street lights off the car windscreen, hence the curve and double back as the car enters the dominance of another lighting column. It’s quite mathematical, and I think it could be modelled with fairly basic locus mathematics.

I could be wrong, though…