It's a Mystery, albeit a very small one

The theme for today's Tiny Tuesday hosted by osuzanna is Mystery Macro.  So here's a not very mysterious macro image. I'll also use it for the AugustPhotoCallenge2017 as today's suggestion is fuzzy, this fuzziness is actually deliberate, unlike a lot of my photos! 

A quiet day sorting photos then meeting Ann for a coffee at Nero after 'work'.