I don’t know what I was doing but I know where I was. At Etruria Flint Mill by the Trent and Mersey canal. How do I know? This picture came up on my phone memories. I love the rainbow flies across the sky with one brilliant end behind the chimney. It looks like a multicoloured comet. I Ts interesting how the area of cloud under rainbows looks paler than the area above. It must be part of the optics of rain storms.