Tiny Tuesday: "Something Rough"

No I haven't got mixed up thinking that it's Abstract Thursday today, although this could qualify for that! In fact it's a very close-up photo of something with a fine rough surface. I won't say what it is until tomorrow but don't spend too long pondering it as it may be tricky. (I'll be very impressed if anyone guesses it - although having said that maybe I'll find that everyone does!).

Many thanks to Incredibish for hosting TT his month.